Class: Array

Inherits:
Object show all
Includes:
Enumerable
Defined in:
array.c

Overview

Arrays are ordered, integer-indexed collections of any object.

Array indexing starts at 0, as in C or Java. A negative index is assumed to be relative to the end of the array—that is, an index of -1 indicates the last element of the array, -2 is the next to last element in the array, and so on.

Creating Arrays

A new array can be created by using the literal constructor []. Arrays can contain different types of objects. For example, the array below contains an Integer, a String and a Float:

ary = [1, "two", 3.0] #=> [1, "two", 3.0]

An array can also be created by explicitly calling Array.new with zero, one (the initial size of the Array) or two arguments (the initial size and a default object).

ary = Array.new    #=> []
Array.new(3)       #=> [nil, nil, nil]
Array.new(3, true) #=> [true, true, true]

Note that the second argument populates the array with references to the same object. Therefore, it is only recommended in cases when you need to instantiate arrays with natively immutable objects such as Symbols, numbers, true or false.

To create an array with separate objects a block can be passed instead. This method is safe to use with mutable objects such as hashes, strings or other arrays:

Array.new(4) { Hash.new } #=> [{}, {}, {}, {}]

This is also a quick way to build up multi-dimensional arrays:

empty_table = Array.new(3) { Array.new(3) }
#=> [[nil, nil, nil], [nil, nil, nil], [nil, nil, nil]]

An array can also be created by using the Array() method, provided by Kernel, which tries to call #to_ary, then #to_a on its argument.

Array(=> “a”, :b => “b”) #=> [[:a, “a”], [:b, “b”]]

Example Usage

In addition to the methods it mixes in through the Enumerable module, the Array class has proprietary methods for accessing, searching and otherwise manipulating arrays.

Some of the more common ones are illustrated below.

Accessing Elements

Elements in an array can be retrieved using the Array#[] method. It can take a single integer argument (a numeric index), a pair of arguments (start and length) or a range. Negative indices start counting from the end, with -1 being the last element.

arr = [1, 2, 3, 4, 5, 6]
arr[2]    #=> 3
arr[100]  #=> nil
arr[-3]   #=> 4
arr[2, 3] #=> [3, 4, 5]
arr[1..4] #=> [2, 3, 4, 5]
arr[1..-3] #=> [2, 3, 4]

Another way to access a particular array element is by using the #at method

arr.at(0) #=> 1

The #slice method works in an identical manner to Array#[].

To raise an error for indices outside of the array bounds or else to provide a default value when that happens, you can use #fetch.

arr = ['a', 'b', 'c', 'd', 'e', 'f']
arr.fetch(100) #=> IndexError: index 100 outside of array bounds: -6...6
arr.fetch(100, "oops") #=> "oops"

The special methods #first and #last will return the first and last elements of an array, respectively.

arr.first #=> 1
arr.last  #=> 6

To return the first n elements of an array, use #take

arr.take(3) #=> [1, 2, 3]

#drop does the opposite of #take, by returning the elements after n elements have been dropped:

arr.drop(3) #=> [4, 5, 6]

Obtaining Information about an Array

Arrays keep track of their own length at all times. To query an array about the number of elements it contains, use #length, #count or #size.

browsers = ['Chrome', 'Firefox', 'Safari', 'Opera', 'IE']
browsers.length #=> 5
browsers.count #=> 5

To check whether an array contains any elements at all

browsers.empty? #=> false

To check whether a particular item is included in the array

browsers.include?('Konqueror') #=> false

Adding Items to Arrays

Items can be added to the end of an array by using either #push or #<<

arr = [1, 2, 3, 4]
arr.push(5) #=> [1, 2, 3, 4, 5]
arr << 6    #=> [1, 2, 3, 4, 5, 6]

#unshift will add a new item to the beginning of an array.

arr.unshift(0) #=> [0, 1, 2, 3, 4, 5, 6]

With #insert you can add a new element to an array at any position.

arr.insert(3, 'apple')  #=> [0, 1, 2, 'apple', 3, 4, 5, 6]

Using the #insert method, you can also insert multiple values at once:

arr.insert(3, 'orange', 'pear', 'grapefruit')
#=> [0, 1, 2, "orange", "pear", "grapefruit", "apple", 3, 4, 5, 6]

Removing Items from an Array

The method #pop removes the last element in an array and returns it:

arr =  [1, 2, 3, 4, 5, 6]
arr.pop #=> 6
arr #=> [1, 2, 3, 4, 5]

To retrieve and at the same time remove the first item, use #shift:

arr.shift #=> 1
arr #=> [2, 3, 4, 5]

To delete an element at a particular index:

arr.delete_at(2) #=> 4
arr #=> [2, 3, 5]

To delete a particular element anywhere in an array, use #delete:

arr = [1, 2, 2, 3]
arr.delete(2) #=> 2
arr #=> [1,3]

A useful method if you need to remove nil values from an array is #compact:

arr = ['foo', 0, nil, 'bar', 7, 'baz', nil]
arr.compact  #=> ['foo', 0, 'bar', 7, 'baz']
arr          #=> ['foo', 0, nil, 'bar', 7, 'baz', nil]
arr.compact! #=> ['foo', 0, 'bar', 7, 'baz']
arr          #=> ['foo', 0, 'bar', 7, 'baz']

Another common need is to remove duplicate elements from an array.

It has the non-destructive #uniq, and destructive method #uniq!

arr = [2, 5, 6, 556, 6, 6, 8, 9, 0, 123, 556]
arr.uniq #=> [2, 5, 6, 556, 8, 9, 0, 123]

Iterating over Arrays

Like all classes that include the Enumerable module, Array has an each method, which defines what elements should be iterated over and how. In case of Array's #each, all elements in the Array instance are yielded to the supplied block in sequence.

Note that this operation leaves the array unchanged.

arr = [1, 2, 3, 4, 5]
arr.each { |a| print a -= 10, " " }
# prints: -9 -8 -7 -6 -5
#=> [1, 2, 3, 4, 5]

Another sometimes useful iterator is #reverse_each which will iterate over the elements in the array in reverse order.

words = %w[first second third fourth fifth sixth]
str = ""
words.reverse_each { |word| str += "#{word} " }
p str #=> "sixth fifth fourth third second first "

The #map method can be used to create a new array based on the original array, but with the values modified by the supplied block:

arr.map { |a| 2*a }   #=> [2, 4, 6, 8, 10]
arr                   #=> [1, 2, 3, 4, 5]
arr.map! { |a| a**2 } #=> [1, 4, 9, 16, 25]
arr                   #=> [1, 4, 9, 16, 25]

Selecting Items from an Array

Elements can be selected from an array according to criteria defined in a block. The selection can happen in a destructive or a non-destructive manner. While the destructive operations will modify the array they were called on, the non-destructive methods usually return a new array with the selected elements, but leave the original array unchanged.

Non-destructive Selection

arr = [1, 2, 3, 4, 5, 6]
arr.select { |a| a > 3 }     #=> [4, 5, 6]
arr.reject { |a| a < 3 }     #=> [3, 4, 5, 6]
arr.drop_while { |a| a < 4 } #=> [4, 5, 6]
arr                          #=> [1, 2, 3, 4, 5, 6]

Destructive Selection

#select! and #reject! are the corresponding destructive methods to #select and #reject

Similar to #select vs. #reject, #delete_if and #keep_if have the exact opposite result when supplied with the same block:

arr.delete_if { |a| a < 4 } #=> [4, 5, 6]
arr                         #=> [4, 5, 6]

arr = [1, 2, 3, 4, 5, 6]
arr.keep_if { |a| a < 4 } #=> [1, 2, 3]
arr                       #=> [1, 2, 3]

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Enumerable

#all?, #chunk, #chunk_while, #collect_concat, #detect, #each_cons, #each_entry, #each_slice, #each_with_index, #each_with_object, #entries, #find, #find_all, #flat_map, #grep, #grep_v, #group_by, #inject, #lazy, #max, #max_by, #member?, #min, #min_by, #minmax, #minmax_by, #none?, #one?, #partition, #reduce, #slice_after, #slice_before, #slice_when, #sort_by

Constructor Details

#new(size = 0, default = nil) ⇒ Object #new(array) ⇒ Object #new(size) {|index| ... } ⇒ Object

Returns a new array.

In the first form, if no arguments are sent, the new array will be empty. When a size and an optional default are sent, an array is created with size copies of default. Take notice that all elements will reference the same object default.

The second form creates a copy of the array passed as a parameter (the array is generated by calling to_ary on the parameter).

first_array = ["Matz", "Guido"]

second_array = Array.new(first_array) #=> ["Matz", "Guido"]

first_array.equal? second_array       #=> false

In the last form, an array of the given size is created. Each element in this array is created by passing the element's index to the given block and storing the return value.

Array.new(3){ |index| index ** 2 }
# => [0, 1, 4]

Common gotchas

When sending the second parameter, the same object will be used as the value for all the array elements:

a = Array.new(2, Hash.new)
# => [{}, {}]

a[0]['cat'] = 'feline'
a # => [{"cat"=>"feline"}, {"cat"=>"feline"}]

a[1]['cat'] = 'Felix'
a # => [{"cat"=>"Felix"}, {"cat"=>"Felix"}]

Since all the Array elements store the same hash, changes to one of them will affect them all.

If multiple copies are what you want, you should use the block version which uses the result of that block each time an element of the array needs to be initialized:

a = Array.new(2) { Hash.new }
a[0]['cat'] = 'feline'
a # => [{"cat"=>"feline"}, {}]

Overloads:



721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
# File 'array.c', line 721

static VALUE
rb_ary_initialize(int argc, VALUE *argv, VALUE ary)
{
    long len;
    VALUE size, val;

    rb_ary_modify(ary);
    if (argc == 0) {
	if (ARY_OWNS_HEAP_P(ary) && RARRAY_CONST_PTR(ary) != 0) {
	    ruby_sized_xfree((void *)RARRAY_CONST_PTR(ary), ARY_HEAP_SIZE(ary));
	}
        rb_ary_unshare_safe(ary);
        FL_SET_EMBED(ary);
	ARY_SET_EMBED_LEN(ary, 0);
	if (rb_block_given_p()) {
	    rb_warning("given block not used");
	}
	return ary;
    }
    rb_scan_args(argc, argv, "02", &size, &val);
    if (argc == 1 && !FIXNUM_P(size)) {
	val = rb_check_array_type(size);
	if (!NIL_P(val)) {
	    rb_ary_replace(ary, val);
	    return ary;
	}
    }

    len = NUM2LONG(size);
    /* NUM2LONG() may call size.to_int, ary can be frozen, modified, etc */
    if (len < 0) {
	rb_raise(rb_eArgError, "negative array size");
    }
    if (len > ARY_MAX_SIZE) {
	rb_raise(rb_eArgError, "array size too big");
    }
    /* recheck after argument conversion */
    rb_ary_modify(ary);
    ary_resize_capa(ary, len);
    if (rb_block_given_p()) {
	long i;

	if (argc == 2) {
	    rb_warn("block supersedes default value argument");
	}
	for (i=0; i<len; i++) {
	    rb_ary_store(ary, i, rb_yield(LONG2NUM(i)));
	    ARY_SET_LEN(ary, i + 1);
	}
    }
    else {
	ary_memfill(ary, 0, len, val);
	ARY_SET_LEN(ary, len);
    }
    return ary;
}

Class Method Details

.[](*args) ⇒ Object

Returns a new array populated with the given objects.

Array.[]( 1, 'a', /^A/ ) # => [1, "a", /^A/]
Array[ 1, 'a', /^A/ ]    # => [1, "a", /^A/]
[ 1, 'a', /^A/ ]         # => [1, "a", /^A/]


786
787
788
789
790
791
792
793
794
795
796
# File 'array.c', line 786

static VALUE
rb_ary_s_create(int argc, VALUE *argv, VALUE klass)
{
    VALUE ary = ary_new(klass, argc);
    if (argc > 0 && argv) {
        ary_memcpy(ary, 0, argc, argv);
        ARY_SET_LEN(ary, argc);
    }

    return ary;
}

.try_convert(obj) ⇒ Array?

Tries to convert obj into an array, using to_ary method. Returns the converted array or nil if obj cannot be converted for any reason. This method can be used to check if an argument is an array.

Array.try_convert([1])   #=> [1]
Array.try_convert("1")   #=> nil

if tmp = Array.try_convert(arg)
  # the argument is an array
elsif tmp = String.try_convert(arg)
  # the argument is a string
end

Returns:



659
660
661
662
663
# File 'array.c', line 659

static VALUE
rb_ary_s_try_convert(VALUE dummy, VALUE ary)
{
    return rb_check_array_type(ary);
}

Instance Method Details

#&(other_ary) ⇒ Object

Set Intersection — Returns a new array containing elements common to the two arrays, excluding any duplicates. The order is preserved from the original array.

It compares elements using their #hash and #eql? methods for efficiency.

[ 1, 1, 3, 5 ] & [ 1, 2, 3 ]                 #=> [ 1, 3 ]
[ 'a', 'b', 'b', 'z' ] & [ 'a', 'b', 'c' ]   #=> [ 'a', 'b' ]

See also Array#uniq.



4130
4131
4132
4133
4134
4135
4136
4137
4138
4139
4140
4141
4142
4143
4144
4145
4146
4147
4148
4149
4150
4151
4152
4153
4154
# File 'array.c', line 4130

static VALUE
rb_ary_and(VALUE ary1, VALUE ary2)
{
    VALUE hash, ary3, v;
    st_table *table;
    st_data_t vv;
    long i;

    ary2 = to_ary(ary2);
    ary3 = rb_ary_new();
    if (RARRAY_LEN(ary2) == 0) return ary3;
    hash = ary_make_hash(ary2);
    table = rb_hash_tbl_raw(hash);

    for (i=0; i<RARRAY_LEN(ary1); i++) {
	v = RARRAY_AREF(ary1, i);
	vv = (st_data_t)v;
	if (st_delete(table, &vv, 0)) {
	    rb_ary_push(ary3, v);
	}
    }
    ary_recycle_hash(hash);

    return ary3;
}

#*(int) ⇒ Object #*(str) ⇒ Object

Repetition — With a String argument, equivalent to ary.join(str).

Otherwise, returns a new array built by concatenating the int copies of self.

[ 1, 2, 3 ] * 3    #=> [ 1, 2, 3, 1, 2, 3, 1, 2, 3 ]
[ 1, 2, 3 ] * ","  #=> "1,2,3"


3680
3681
3682
3683
3684
3685
3686
3687
3688
3689
3690
3691
3692
3693
3694
3695
3696
3697
3698
3699
3700
3701
3702
3703
3704
3705
3706
3707
3708
3709
3710
3711
3712
3713
3714
3715
3716
3717
3718
3719
3720
3721
3722
3723
3724
# File 'array.c', line 3680

static VALUE
rb_ary_times(VALUE ary, VALUE times)
{
    VALUE ary2, tmp;
    const VALUE *ptr;
    long t, len;

    tmp = rb_check_string_type(times);
    if (!NIL_P(tmp)) {
	return rb_ary_join(ary, tmp);
    }

    len = NUM2LONG(times);
    if (len == 0) {
	ary2 = ary_new(rb_obj_class(ary), 0);
	goto out;
    }
    if (len < 0) {
	rb_raise(rb_eArgError, "negative argument");
    }
    if (ARY_MAX_SIZE/len < RARRAY_LEN(ary)) {
	rb_raise(rb_eArgError, "argument too big");
    }
    len *= RARRAY_LEN(ary);

    ary2 = ary_new(rb_obj_class(ary), len);
    ARY_SET_LEN(ary2, len);

    ptr = RARRAY_CONST_PTR(ary);
    t = RARRAY_LEN(ary);
    if (0 < t) {
	ary_memcpy(ary2, 0, t, ptr);
	while (t <= len/2) {
	    ary_memcpy(ary2, t, t, RARRAY_CONST_PTR(ary2));
            t *= 2;
        }
        if (t < len) {
	    ary_memcpy(ary2, t, len-t, RARRAY_CONST_PTR(ary2));
        }
    }
  out:
    OBJ_INFECT(ary2, ary);

    return ary2;
}

#+(other_ary) ⇒ Object

Concatenation — Returns a new array built by concatenating the two arrays together to produce a third array.

[ 1, 2, 3 ] + [ 4, 5 ]    #=> [ 1, 2, 3, 4, 5 ]
a = [ "a", "b", "c" ]
c = a + [ "d", "e", "f" ]
c                         #=> [ "a", "b", "c", "d", "e", "f" ]
a                         #=> [ "a", "b", "c" ]

Note that

x += y

is the same as

x = x + y

This means that it produces a new array. As a consequence, repeated use of += on arrays can be quite inefficient.

See also Array#concat.



3619
3620
3621
3622
3623
3624
3625
3626
3627
3628
3629
3630
3631
3632
3633
3634
3635
# File 'array.c', line 3619

VALUE
rb_ary_plus(VALUE x, VALUE y)
{
    VALUE z;
    long len, xlen, ylen;

    y = to_ary(y);
    xlen = RARRAY_LEN(x);
    ylen = RARRAY_LEN(y);
    len = xlen + ylen;
    z = rb_ary_new2(len);

    ary_memcpy(z, 0, xlen, RARRAY_CONST_PTR(x));
    ary_memcpy(z, xlen, ylen, RARRAY_CONST_PTR(y));
    ARY_SET_LEN(z, len);
    return z;
}

#-(other_ary) ⇒ Object

Array Difference

Returns a new array that is a copy of the original array, removing any items that also appear in other_ary. The order is preserved from the original array.

It compares elements using their #hash and #eql? methods for efficiency.

[ 1, 1, 2, 2, 3, 3, 4, 5 ] - [ 1, 2, 4 ]  #=>  [ 3, 3, 5 ]

If you need set-like behavior, see the library class Set.



4095
4096
4097
4098
4099
4100
4101
4102
4103
4104
4105
4106
4107
4108
4109
4110
4111
# File 'array.c', line 4095

static VALUE
rb_ary_diff(VALUE ary1, VALUE ary2)
{
    VALUE ary3;
    VALUE hash;
    long i;

    hash = ary_make_hash(to_ary(ary2));
    ary3 = rb_ary_new();

    for (i=0; i<RARRAY_LEN(ary1); i++) {
	if (st_lookup(rb_hash_tbl_raw(hash), RARRAY_AREF(ary1, i), 0)) continue;
	rb_ary_push(ary3, rb_ary_elt(ary1, i));
    }
    ary_recycle_hash(hash);
    return ary3;
}

#<<(obj) ⇒ Object

Append—Pushes the given object on to the end of this array. This expression returns the array itself, so several appends may be chained together.

[ 1, 2 ] << "c" << "d" << [ 3, 4 ]
        #=>  [ 1, 2, "c", "d", [ 3, 4 ] ]


904
905
906
907
908
909
910
911
912
913
914
# File 'array.c', line 904

VALUE
rb_ary_push(VALUE ary, VALUE item)
{
    long idx = RARRAY_LEN(ary);
    VALUE target_ary = ary_ensure_room_for_push(ary, 1);
    RARRAY_PTR_USE(ary, ptr, {
	RB_OBJ_WRITE(target_ary, &ptr[idx], item);
    });
    ARY_SET_LEN(ary, idx + 1);
    return ary;
}

#<=>(other_ary) ⇒ -1, ...

Comparison — Returns an integer (-1, 0, or +1) if this array is less than, equal to, or greater than other_ary.

Each object in each array is compared (using the <=> operator).

Arrays are compared in an “element-wise” manner; the first element of ary is compared with the first one of other_ary using the <=> operator, then each of the second elements, etc… As soon as the result of any such comparison is non zero (i.e. the two corresponding elements are not equal), that result is returned for the whole array comparison.

If all the elements are equal, then the result is based on a comparison of the array lengths. Thus, two arrays are “equal” according to Array#<=> if, and only if, they have the same length and the value of each element is equal to the value of the corresponding element in the other array.

nil is returned if the other_ary is not an array or if the comparison of two elements returned nil.

[ "a", "a", "c" ]    <=> [ "a", "b", "c" ]   #=> -1
[ 1, 2, 3, 4, 5, 6 ] <=> [ 1, 2 ]            #=> +1
[ 1, 2 ]             <=> [ 1, :two ]         #=> nil

Returns:

  • (-1, 0, +1, nil)


3999
4000
4001
4002
4003
4004
4005
4006
4007
4008
4009
4010
4011
4012
4013
4014
# File 'array.c', line 3999

VALUE
rb_ary_cmp(VALUE ary1, VALUE ary2)
{
    long len;
    VALUE v;

    ary2 = rb_check_array_type(ary2);
    if (NIL_P(ary2)) return Qnil;
    if (ary1 == ary2) return INT2FIX(0);
    v = rb_exec_recursive_paired(recursive_cmp, ary1, ary2, ary2);
    if (v != Qundef) return v;
    len = RARRAY_LEN(ary1) - RARRAY_LEN(ary2);
    if (len == 0) return INT2FIX(0);
    if (len > 0) return INT2FIX(1);
    return INT2FIX(-1);
}

#==(other_ary) ⇒ Boolean

Equality — Two arrays are equal if they contain the same number of elements and if each element is equal to (according to Object#==) the corresponding element in other_ary.

[ "a", "c" ]    == [ "a", "c", 7 ]     #=> false
[ "a", "c", 7 ] == [ "a", "c", 7 ]     #=> true
[ "a", "c", 7 ] == [ "a", "d", "f" ]   #=> false

Returns:

  • (Boolean)


3842
3843
3844
3845
3846
3847
3848
3849
3850
3851
3852
3853
3854
3855
# File 'array.c', line 3842

static VALUE
rb_ary_equal(VALUE ary1, VALUE ary2)
{
    if (ary1 == ary2) return Qtrue;
    if (!RB_TYPE_P(ary2, T_ARRAY)) {
	if (!rb_respond_to(ary2, idTo_ary)) {
	    return Qfalse;
	}
	return rb_equal(ary2, ary1);
    }
    if (RARRAY_LEN(ary1) != RARRAY_LEN(ary2)) return Qfalse;
    if (RARRAY_CONST_PTR(ary1) == RARRAY_CONST_PTR(ary2)) return Qtrue;
    return rb_exec_recursive_paired(recursive_equal, ary1, ary2, ary2);
}

#[](index) ⇒ Object? #[](start, length) ⇒ nil #[](range) ⇒ nil #slice(index) ⇒ Object? #slice(start, length) ⇒ nil #slice(range) ⇒ nil

Element Reference — Returns the element at index, or returns a subarray starting at the start index and continuing for length elements, or returns a subarray specified by range of indices.

Negative indices count backward from the end of the array (-1 is the last element). For start and range cases the starting index is just before an element. Additionally, an empty array is returned when the starting index for an element range is at the end of the array.

Returns nil if the index (or starting index) are out of range.

a = [ "a", "b", "c", "d", "e" ]
a[2] +  a[0] + a[1]    #=> "cab"
a[6]                   #=> nil
a[1, 2]                #=> [ "b", "c" ]
a[1..3]                #=> [ "b", "c", "d" ]
a[4..7]                #=> [ "e" ]
a[6..10]               #=> nil
a[-3, 3]               #=> [ "c", "d", "e" ]
# special cases
a[5]                   #=> nil
a[6, 1]                #=> nil
a[5, 1]                #=> []
a[5..10]               #=> []

Overloads:

  • #[](index) ⇒ Object?

    Returns:

  • #[](start, length) ⇒ nil

    Returns:

    • (nil)
  • #[](range) ⇒ nil

    Returns:

    • (nil)
  • #slice(index) ⇒ Object?

    Returns:

  • #slice(start, length) ⇒ nil

    Returns:

    • (nil)
  • #slice(range) ⇒ nil

    Returns:

    • (nil)


1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
# File 'array.c', line 1258

VALUE
rb_ary_aref(int argc, const VALUE *argv, VALUE ary)
{
    VALUE arg;
    long beg, len;

    if (argc == 2) {
	beg = NUM2LONG(argv[0]);
	len = NUM2LONG(argv[1]);
	if (beg < 0) {
	    beg += RARRAY_LEN(ary);
	}
	return rb_ary_subseq(ary, beg, len);
    }
    if (argc != 1) {
	rb_scan_args(argc, argv, "11", NULL, NULL);
    }
    arg = argv[0];
    /* special case - speeding up */
    if (FIXNUM_P(arg)) {
	return rb_ary_entry(ary, FIX2LONG(arg));
    }
    /* check if idx is Range */
    switch (rb_range_beg_len(arg, &beg, &len, RARRAY_LEN(ary), 0)) {
      case Qfalse:
	break;
      case Qnil:
	return Qnil;
      default:
	return rb_ary_subseq(ary, beg, len);
    }
    return rb_ary_entry(ary, NUM2LONG(arg));
}

#[]=(index) ⇒ Object #[]=(start, length) ⇒ Object? #[]=(range) ⇒ Object?

Element Assignment — Sets the element at index, or replaces a subarray from the start index for length elements, or replaces a subarray specified by the range of indices.

If indices are greater than the current capacity of the array, the array grows automatically. Elements are inserted into the array at start if length is zero.

Negative indices will count backward from the end of the array. For start and range cases the starting index is just before an element.

An IndexError is raised if a negative index points past the beginning of the array.

See also Array#push, and Array#unshift.

a = Array.new
a[4] = "4";                 #=> [nil, nil, nil, nil, "4"]
a[0, 3] = [ 'a', 'b', 'c' ] #=> ["a", "b", "c", nil, "4"]
a[1..2] = [ 1, 2 ]          #=> ["a", 1, 2, nil, "4"]
a[0, 2] = "?"               #=> ["?", 2, nil, "4"]
a[0..2] = "A"               #=> ["A", "4"]
a[-1]   = "Z"               #=> ["A", "Z"]
a[1..-1] = nil              #=> ["A", nil]
a[1..-1] = []               #=> ["A"]
a[0, 0] = [ 1, 2 ]          #=> [1, 2, "A"]
a[3, 0] = "B"               #=> [1, 2, "A", "B"]

Overloads:



1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
# File 'array.c', line 1716

static VALUE
rb_ary_aset(int argc, VALUE *argv, VALUE ary)
{
    long offset, beg, len;

    if (argc == 3) {
	rb_ary_modify_check(ary);
	beg = NUM2LONG(argv[0]);
	len = NUM2LONG(argv[1]);
	rb_ary_splice(ary, beg, len, argv[2]);
	return argv[2];
    }
    rb_check_arity(argc, 2, 2);
    rb_ary_modify_check(ary);
    if (FIXNUM_P(argv[0])) {
	offset = FIX2LONG(argv[0]);
	goto fixnum;
    }
    if (rb_range_beg_len(argv[0], &beg, &len, RARRAY_LEN(ary), 1)) {
	/* check if idx is Range */
	rb_ary_splice(ary, beg, len, argv[1]);
	return argv[1];
    }

    offset = NUM2LONG(argv[0]);
fixnum:
    rb_ary_store(ary, offset, argv[1]);
    return argv[1];
}

#any? {|obj| ... } ⇒ Boolean

See also Enumerable#any?

Yields:

  • (obj)

Returns:

  • (Boolean)

Returns:

  • (Boolean)


5516
5517
5518
5519
5520
5521
5522
5523
5524
5525
5526
5527
5528
5529
5530
5531
5532
# File 'array.c', line 5516

static VALUE
rb_ary_any_p(VALUE ary)
{
    long i, len = RARRAY_LEN(ary);
    const VALUE *ptr = RARRAY_CONST_PTR(ary);

    if (!len) return Qfalse;
    if (!rb_block_given_p()) {
	for (i = 0; i < len; ++i) if (RTEST(ptr[i])) return Qtrue;
    }
    else {
	for (i = 0; i < RARRAY_LEN(ary); ++i) {
	    if (RTEST(rb_yield(RARRAY_AREF(ary, i)))) return Qtrue;
	}
    }
    return Qfalse;
}

#assoc(obj) ⇒ nil

Searches through an array whose elements are also arrays comparing obj with the first element of each contained array using obj.==.

Returns the first contained array that matches (that is, the first associated array), or nil if no match is found.

See also Array#rassoc

s1 = [ "colors", "red", "blue", "green" ]
s2 = [ "letters", "a", "b", "c" ]
s3 = "foo"
a  = [ s1, s2, s3 ]
a.assoc("letters")  #=> [ "letters", "a", "b", "c" ]
a.assoc("foo")      #=> nil

Returns:

  • (nil)


3746
3747
3748
3749
3750
3751
3752
3753
3754
3755
3756
3757
3758
3759
# File 'array.c', line 3746

VALUE
rb_ary_assoc(VALUE ary, VALUE key)
{
    long i;
    VALUE v;

    for (i = 0; i < RARRAY_LEN(ary); ++i) {
	v = rb_check_array_type(RARRAY_AREF(ary, i));
	if (!NIL_P(v) && RARRAY_LEN(v) > 0 &&
	    rb_equal(RARRAY_AREF(v, 0), key))
	    return v;
    }
    return Qnil;
}

#at(index) ⇒ Object?

Returns the element at index. A negative index counts from the end of self. Returns nil if the index is out of range. See also Array#[].

a = [ "a", "b", "c", "d", "e" ]
a.at(0)     #=> "a"
a.at(-1)    #=> "e"

Returns:



1305
1306
1307
1308
1309
# File 'array.c', line 1305

VALUE
rb_ary_at(VALUE ary, VALUE pos)
{
    return rb_ary_entry(ary, NUM2LONG(pos));
}

#bsearch {|x| ... } ⇒ Object

By using binary search, finds a value from this array which meets the given condition in O(log n) where n is the size of the array.

You can use this method in two use cases: a find-minimum mode and a find-any mode. In either case, the elements of the array must be monotone (or sorted) with respect to the block.

In find-minimum mode (this is a good choice for typical use case), the block must return true or false, and there must be an index i (0 <= i <= ary.size) so that:

  • the block returns false for any element whose index is less than i, and

  • the block returns true for any element whose index is greater than or equal to i.

This method returns the i-th element. If i is equal to ary.size, it returns nil.

ary = [0, 4, 7, 10, 12]
ary.bsearch {|x| x >=   4 } #=> 4
ary.bsearch {|x| x >=   6 } #=> 7
ary.bsearch {|x| x >=  -1 } #=> 0
ary.bsearch {|x| x >= 100 } #=> nil

In find-any mode (this behaves like libc's bsearch(3)), the block must return a number, and there must be two indices i and j (0 <= i <= j <= ary.size) so that:

  • the block returns a positive number for ary if 0 <= k < i,

  • the block returns zero for ary if i <= k < j, and

  • the block returns a negative number for ary if j <= k < ary.size.

Under this condition, this method returns any element whose index is within i…j. If i is equal to j (i.e., there is no element that satisfies the block), this method returns nil.

ary = [0, 4, 7, 10, 12]
# try to find v such that 4 <= v < 8
ary.bsearch {|x| 1 - x / 4 } #=> 4 or 7
# try to find v such that 8 <= v < 10
ary.bsearch {|x| 4 - x / 2 } #=> nil

You must not mix the two modes at a time; the block must always return either true/false, or always return a number. It is undefined which value is actually picked up at each iteration.

Yields:

  • (x)


2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
# File 'array.c', line 2600

static VALUE
rb_ary_bsearch(VALUE ary)
{
    VALUE index_result = rb_ary_bsearch_index(ary);

    if (FIXNUM_P(index_result)) {
	return rb_ary_entry(ary, FIX2LONG(index_result));
    }
    return index_result;
}

#bsearch_index {|x| ... } ⇒ Integer?

By using binary search, finds an index of a value from this array which meets the given condition in O(log n) where n is the size of the array.

It supports two modes, depending on the nature of the block and they are exactly the same as in the case of #bsearch method with the only difference being that this method returns the index of the element instead of the element itself. For more details consult the documentation for #bsearch.

Yields:

  • (x)

Returns:



2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
# File 'array.c', line 2624

static VALUE
rb_ary_bsearch_index(VALUE ary)
{
    long low = 0, high = RARRAY_LEN(ary), mid;
    int smaller = 0, satisfied = 0;
    VALUE v, val;

    RETURN_ENUMERATOR(ary, 0, 0);
    while (low < high) {
	mid = low + ((high - low) / 2);
	val = rb_ary_entry(ary, mid);
	v = rb_yield(val);
	if (FIXNUM_P(v)) {
	    if (v == INT2FIX(0)) return INT2FIX(mid);
	    smaller = (SIGNED_VALUE)v < 0; /* Fixnum preserves its sign-bit */
	}
	else if (v == Qtrue) {
	    satisfied = 1;
	    smaller = 1;
	}
	else if (v == Qfalse || v == Qnil) {
	    smaller = 0;
	}
	else if (rb_obj_is_kind_of(v, rb_cNumeric)) {
	    const VALUE zero = INT2FIX(0);
	    switch (rb_cmpint(rb_funcallv(v, id_cmp, 1, &zero), v, zero)) {
	      case 0: return INT2FIX(mid);
	      case 1: smaller = 1; break;
	      case -1: smaller = 0;
	    }
	}
	else {
	    rb_raise(rb_eTypeError, "wrong argument type %"PRIsVALUE
		     " (must be numeric, true, false or nil)",
		     rb_obj_class(v));
	}
	if (smaller) {
	    high = mid;
	}
	else {
	    low = mid + 1;
	}
    }
    if (!satisfied) return Qnil;
    return INT2FIX(low);
}

#clearObject

Removes all elements from self.

a = [ "a", "b", "c", "d", "e" ]
a.clear    #=> [ ]


3483
3484
3485
3486
3487
3488
3489
3490
3491
3492
3493
3494
3495
3496
3497
3498
# File 'array.c', line 3483

VALUE
rb_ary_clear(VALUE ary)
{
    rb_ary_modify_check(ary);
    ARY_SET_LEN(ary, 0);
    if (ARY_SHARED_P(ary)) {
	if (!ARY_EMBED_P(ary)) {
	    rb_ary_unshare(ary);
	    FL_SET_EMBED(ary);
	}
    }
    else if (ARY_DEFAULT_SIZE * 2 < ARY_CAPA(ary)) {
	ary_resize_capa(ary, ARY_DEFAULT_SIZE * 2);
    }
    return ary;
}

#collect {|item| ... } ⇒ Object #map {|item| ... } ⇒ Object #collectEnumerator #mapEnumerator

Invokes the given block once for each element of self.

Creates a new array containing the values returned by the block.

See also Enumerable#collect.

If no block is given, an Enumerator is returned instead.

a = [ "a", "b", "c", "d" ]
a.collect { |x| x + "!" }         #=> ["a!", "b!", "c!", "d!"]
a.map.with_index { |x, i| x * i } #=> ["", "b", "cc", "ddd"]
a                                 #=> ["a", "b", "c", "d"]

Overloads:



2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
# File 'array.c', line 2724

static VALUE
rb_ary_collect(VALUE ary)
{
    long i;
    VALUE collect;

    RETURN_SIZED_ENUMERATOR(ary, 0, 0, ary_enum_length);
    collect = rb_ary_new2(RARRAY_LEN(ary));
    for (i = 0; i < RARRAY_LEN(ary); i++) {
	rb_ary_push(collect, rb_yield(RARRAY_AREF(ary, i)));
    }
    return collect;
}

#collect! {|item| ... } ⇒ Object #map! {|item| ... } ⇒ Object #collect!Enumerator #map!Enumerator

Invokes the given block once for each element of self, replacing the element with the value returned by the block.

See also Enumerable#collect.

If no block is given, an Enumerator is returned instead.

a = [ "a", "b", "c", "d" ]
a.map! {|x| x + "!" }
a #=>  [ "a!", "b!", "c!", "d!" ]
a.collect!.with_index {|x, i| x[0...i] }
a #=>  ["", "b", "c!", "d!"]

Overloads:



2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
# File 'array.c', line 2760

static VALUE
rb_ary_collect_bang(VALUE ary)
{
    long i;

    RETURN_SIZED_ENUMERATOR(ary, 0, 0, ary_enum_length);
    rb_ary_modify(ary);
    for (i = 0; i < RARRAY_LEN(ary); i++) {
	rb_ary_store(ary, i, rb_yield(RARRAY_AREF(ary, i)));
    }
    return ary;
}

#combination(n) {|c| ... } ⇒ Object #combination(n) ⇒ Enumerator

When invoked with a block, yields all combinations of length n of elements from the array and then returns the array itself.

The implementation makes no guarantees about the order in which the combinations are yielded.

If no block is given, an Enumerator is returned instead.

Examples:

a = [1, 2, 3, 4]
a.combination(1).to_a  #=> [[1],[2],[3],[4]]
a.combination(2).to_a  #=> [[1,2],[1,3],[1,4],[2,3],[2,4],[3,4]]
a.combination(3).to_a  #=> [[1,2,3],[1,2,4],[1,3,4],[2,3,4]]
a.combination(4).to_a  #=> [[1,2,3,4]]
a.combination(0).to_a  #=> [[]] # one combination of length 0
a.combination(5).to_a  #=> []   # no combinations of length 5

Overloads:



5051
5052
5053
5054
5055
5056
5057
5058
5059
5060
5061
5062
5063
5064
5065
5066
5067
5068
5069
5070
5071
5072
5073
5074
5075
5076
5077
5078
5079
5080
5081
# File 'array.c', line 5051

static VALUE
rb_ary_combination(VALUE ary, VALUE num)
{
    long i, n, len;

    n = NUM2LONG(num);
    RETURN_SIZED_ENUMERATOR(ary, 1, &num, rb_ary_combination_size);
    len = RARRAY_LEN(ary);
    if (n < 0 || len < n) {
	/* yield nothing */
    }
    else if (n == 0) {
	rb_yield(rb_ary_new2(0));
    }
    else if (n == 1) {
	for (i = 0; i < len; i++) {
	    rb_yield(rb_ary_new3(1, RARRAY_AREF(ary, i)));
	}
    }
    else {
	VALUE ary0 = ary_make_shared_copy(ary); /* private defensive copy of ary */
	volatile VALUE t0;
	long *stack = ALLOCV_N(long, t0, n+1);

	RBASIC_CLEAR_CLASS(ary0);
	combinate0(len, n, stack, ary0);
	ALLOCV_END(t0);
	RBASIC_SET_CLASS_RAW(ary0, rb_cArray);
    }
    return ary;
}

#compactObject

Returns a copy of self with all nil elements removed.

[ "a", nil, "b", nil, "c", nil ].compact
                  #=> [ "a", "b", "c" ]


4350
4351
4352
4353
4354
4355
4356
# File 'array.c', line 4350

static VALUE
rb_ary_compact(VALUE ary)
{
    ary = rb_ary_dup(ary);
    rb_ary_compact_bang(ary);
    return ary;
}

#compact!nil

Removes nil elements from the array.

Returns nil if no changes were made, otherwise returns the array.

[ "a", nil, "b", nil, "c" ].compact! #=> [ "a", "b", "c" ]
[ "a", "b", "c" ].compact!           #=> nil

Returns:

  • (nil)


4317
4318
4319
4320
4321
4322
4323
4324
4325
4326
4327
4328
4329
4330
4331
4332
4333
4334
4335
4336
4337
4338
# File 'array.c', line 4317

static VALUE
rb_ary_compact_bang(VALUE ary)
{
    VALUE *p, *t, *end;
    long n;

    rb_ary_modify(ary);
    p = t = (VALUE *)RARRAY_CONST_PTR(ary); /* WB: no new reference */
    end = p + RARRAY_LEN(ary);

    while (t < end) {
	if (NIL_P(*t)) t++;
	else *p++ = *t++;
    }
    n = p - RARRAY_CONST_PTR(ary);
    if (RARRAY_LEN(ary) == n) {
	return Qnil;
    }
    ary_resize_smaller(ary, n);

    return ary;
}

#concat(other_ary) ⇒ Object

Appends the elements of other_ary to self.

[ "a", "b" ].concat( ["c", "d"] ) #=> [ "a", "b", "c", "d" ]
a = [ 1, 2, 3 ]
a.concat( [ 4, 5 ] )
a                                 #=> [ 1, 2, 3, 4, 5 ]

See also Array#+.



3651
3652
3653
3654
3655
3656
3657
3658
3659
3660
# File 'array.c', line 3651

VALUE
rb_ary_concat(VALUE x, VALUE y)
{
    rb_ary_modify_check(x);
    y = to_ary(y);
    if (RARRAY_LEN(y) > 0) {
	rb_ary_splice(x, RARRAY_LEN(x), 0, y);
    }
    return x;
}

#countInteger #count(obj) ⇒ Integer #count {|item| ... } ⇒ Integer

Returns the number of elements.

If an argument is given, counts the number of elements which equal obj using ==.

If a block is given, counts the number of elements for which the block returns a true value.

ary = [1, 2, 4, 2]
ary.count                  #=> 4
ary.count(2)               #=> 2
ary.count { |x| x%2 == 0 } #=> 3

Overloads:



4379
4380
4381
4382
4383
4384
4385
4386
4387
4388
4389
4390
4391
4392
4393
4394
4395
4396
4397
4398
4399
4400
4401
4402
4403
4404
4405
4406
4407
4408
# File 'array.c', line 4379

static VALUE
rb_ary_count(int argc, VALUE *argv, VALUE ary)
{
    long i, n = 0;

    if (argc == 0) {
	VALUE v;

	if (!rb_block_given_p())
	    return LONG2NUM(RARRAY_LEN(ary));

	for (i = 0; i < RARRAY_LEN(ary); i++) {
	    v = RARRAY_AREF(ary, i);
	    if (RTEST(rb_yield(v))) n++;
	}
    }
    else {
	VALUE obj;

	rb_scan_args(argc, argv, "1", &obj);
	if (rb_block_given_p()) {
	    rb_warn("given block not used");
	}
	for (i = 0; i < RARRAY_LEN(ary); i++) {
	    if (rb_equal(RARRAY_AREF(ary, i), obj)) n++;
	}
    }

    return LONG2NUM(n);
}

#cycle(n = nil) {|obj| ... } ⇒ nil #cycle(n = nil) ⇒ Enumerator

Calls the given block for each element n times or forever if nil is given.

Does nothing if a non-positive number is given or the array is empty.

Returns nil if the loop has finished without getting interrupted.

If no block is given, an Enumerator is returned instead.

a = ["a", "b", "c"]
a.cycle { |x| puts x }     # print, a, b, c, a, b, c,.. forever.
a.cycle(2) { |x| puts x }  # print, a, b, c, a, b, c.

Overloads:

  • #cycle(n = nil) {|obj| ... } ⇒ nil

    Yields:

    • (obj)

    Returns:

    • (nil)
  • #cycle(n = nil) ⇒ Enumerator

    Returns:



4795
4796
4797
4798
4799
4800
4801
4802
4803
4804
4805
4806
4807
4808
4809
4810
4811
4812
4813
4814
4815
4816
4817
4818
# File 'array.c', line 4795

static VALUE
rb_ary_cycle(int argc, VALUE *argv, VALUE ary)
{
    long n, i;
    VALUE nv = Qnil;

    rb_scan_args(argc, argv, "01", &nv);

    RETURN_SIZED_ENUMERATOR(ary, argc, argv, rb_ary_cycle_size);
    if (NIL_P(nv)) {
        n = -1;
    }
    else {
        n = NUM2LONG(nv);
        if (n <= 0) return Qnil;
    }

    while (RARRAY_LEN(ary) > 0 && (n < 0 || 0 < n--)) {
        for (i=0; i<RARRAY_LEN(ary); i++) {
            rb_yield(RARRAY_AREF(ary, i));
        }
    }
    return Qnil;
}

#delete(obj) ⇒ nil #delete(obj) { ... } ⇒ Object

Deletes all items from self that are equal to obj.

Returns the last deleted item, or nil if no matching item is found.

If the optional code block is given, the result of the block is returned if the item is not found. (To remove nil elements and get an informative return value, use Array#compact!)

a = [ "a", "b", "b", "b", "c" ]
a.delete("b")                   #=> "b"
a                               #=> ["a", "c"]
a.delete("z")                   #=> nil
a.delete("z") { "not found" }   #=> "not found"

Overloads:

  • #delete(obj) ⇒ nil

    Returns:

    • (nil)
  • #delete(obj) { ... } ⇒ Object

    Yields:



2988
2989
2990
2991
2992
2993
2994
2995
2996
2997
2998
2999
3000
3001
3002
3003
3004
3005
3006
3007
3008
3009
3010
3011
3012
3013
3014
3015
3016
# File 'array.c', line 2988

VALUE
rb_ary_delete(VALUE ary, VALUE item)
{
    VALUE v = item;
    long i1, i2;

    for (i1 = i2 = 0; i1 < RARRAY_LEN(ary); i1++) {
	VALUE e = RARRAY_AREF(ary, i1);

	if (rb_equal(e, item)) {
	    v = e;
	    continue;
	}
	if (i1 != i2) {
	    rb_ary_store(ary, i2, e);
	}
	i2++;
    }
    if (RARRAY_LEN(ary) == i2) {
	if (rb_block_given_p()) {
	    return rb_yield(item);
	}
	return Qnil;
    }

    ary_resize_smaller(ary, i2);

    return v;
}

#delete_at(index) ⇒ Object?

Deletes the element at the specified index, returning that element, or nil if the index is out of range.

See also Array#slice!

a = ["ant", "bat", "cat", "dog"]
a.delete_at(2)    #=> "cat"
a                 #=> ["ant", "bat", "dog"]
a.delete_at(99)   #=> nil

Returns:



3078
3079
3080
3081
3082
# File 'array.c', line 3078

static VALUE
rb_ary_delete_at_m(VALUE ary, VALUE pos)
{
    return rb_ary_delete_at(ary, NUM2LONG(pos));
}

#delete_if {|item| ... } ⇒ Object #delete_ifEnumerator

Deletes every element of self for which block evaluates to true.

The array is changed instantly every time the block is called, not after the iteration is over.

See also Array#reject!

If no block is given, an Enumerator is returned instead.

scores = [ 97, 42, 75 ]
scores.delete_if {|score| score < 80 }   #=> [97]

Overloads:



3263
3264
3265
3266
3267
3268
3269
# File 'array.c', line 3263

static VALUE
rb_ary_delete_if(VALUE ary)
{
    RETURN_SIZED_ENUMERATOR(ary, 0, 0, ary_enum_length);
    ary_reject_bang(ary);
    return ary;
}

#dig(idx, ...) ⇒ Object

Extracts the nested value specified by the sequence of idx objects by calling dig at each step, returning nil if any intermediate step is nil.

a = [[1, [2, 3]]]

a.dig(0, 1, 1)                    #=> 3
a.dig(1, 2, 3)                    #=> nil
a.dig(0, 0, 0)                    #=> NoMethodError, undefined method `dig' for 1:Fixnum
[42, {foo: :bar}].dig(1, :foo)    #=> :bar

Returns:



5550
5551
5552
5553
5554
5555
5556
5557
5558
# File 'array.c', line 5550

VALUE
rb_ary_dig(int argc, VALUE *argv, VALUE self)
{
    rb_check_arity(argc, 1, UNLIMITED_ARGUMENTS);
    self = rb_ary_at(self, *argv);
    if (!--argc) return self;
    ++argv;
    return rb_obj_dig(argc, argv, self, Qnil);
}

#drop(n) ⇒ Object

Drops first n elements from ary and returns the rest of the elements in an array.

If a negative number is given, raises an ArgumentError.

See also Array#take

a = [1, 2, 3, 4, 5, 0]
a.drop(3)             #=> [4, 5, 0]


5465
5466
5467
5468
5469
5470
5471
5472
5473
5474
5475
5476
5477
# File 'array.c', line 5465

static VALUE
rb_ary_drop(VALUE ary, VALUE n)
{
    VALUE result;
    long pos = NUM2LONG(n);
    if (pos < 0) {
	rb_raise(rb_eArgError, "attempt to drop negative size");
    }

    result = rb_ary_subseq(ary, pos, RARRAY_LEN(ary));
    if (result == Qnil) result = rb_ary_new();
    return result;
}

#drop_while {|obj| ... } ⇒ Object #drop_whileEnumerator

Drops elements up to, but not including, the first element for which the block returns nil or false and returns an array containing the remaining elements.

If no block is given, an Enumerator is returned instead.

See also Array#take_while

a = [1, 2, 3, 4, 5, 0]
a.drop_while {|i| i < 3 }   #=> [3, 4, 5, 0]

Overloads:



5497
5498
5499
5500
5501
5502
5503
5504
5505
5506
5507
# File 'array.c', line 5497

static VALUE
rb_ary_drop_while(VALUE ary)
{
    long i;

    RETURN_ENUMERATOR(ary, 0, 0);
    for (i = 0; i < RARRAY_LEN(ary); i++) {
	if (!RTEST(rb_yield(RARRAY_AREF(ary, i)))) break;
    }
    return rb_ary_drop(ary, LONG2FIX(i));
}

#each {|item| ... } ⇒ Object #eachEnumerator

Calls the given block once for each element in self, passing that element as a parameter. Returns the array itself.

If no block is given, an Enumerator is returned.

a = [ "a", "b", "c" ]
a.each {|x| print x, " -- " }

produces:

a -- b -- c --

Overloads:



1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
# File 'array.c', line 1808

VALUE
rb_ary_each(VALUE ary)
{
    long i;

    RETURN_SIZED_ENUMERATOR(ary, 0, 0, ary_enum_length);
    for (i=0; i<RARRAY_LEN(ary); i++) {
	rb_yield(RARRAY_AREF(ary, i));
    }
    return ary;
}

#each_index {|index| ... } ⇒ Object #each_indexEnumerator

Same as Array#each, but passes the index of the element instead of the element itself.

An Enumerator is returned if no block is given.

a = [ "a", "b", "c" ]
a.each_index {|x| print x, " -- " }

produces:

0 -- 1 -- 2 --

Overloads:



1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
# File 'array.c', line 1838

static VALUE
rb_ary_each_index(VALUE ary)
{
    long i;
    RETURN_SIZED_ENUMERATOR(ary, 0, 0, ary_enum_length);

    for (i=0; i<RARRAY_LEN(ary); i++) {
	rb_yield(LONG2NUM(i));
    }
    return ary;
}

#empty?Boolean

Returns true if self contains no elements.

[].empty?   #=> true

Returns:

  • (Boolean)

Returns:

  • (Boolean)


1909
1910
1911
1912
1913
1914
1915
# File 'array.c', line 1909

static VALUE
rb_ary_empty_p(VALUE ary)
{
    if (RARRAY_LEN(ary) == 0)
	return Qtrue;
    return Qfalse;
}

#eql?(other) ⇒ Boolean

Returns true if self and other are the same object, or are both arrays with the same content (according to Object#eql?).

Returns:

  • (Boolean)

Returns:

  • (Boolean)


3878
3879
3880
3881
3882
3883
3884
3885
3886
# File 'array.c', line 3878

static VALUE
rb_ary_eql(VALUE ary1, VALUE ary2)
{
    if (ary1 == ary2) return Qtrue;
    if (!RB_TYPE_P(ary2, T_ARRAY)) return Qfalse;
    if (RARRAY_LEN(ary1) != RARRAY_LEN(ary2)) return Qfalse;
    if (RARRAY_CONST_PTR(ary1) == RARRAY_CONST_PTR(ary2)) return Qtrue;
    return rb_exec_recursive_paired(recursive_eql, ary1, ary2, ary2);
}

#fetch(index) ⇒ Object #fetch(index, default) ⇒ Object #fetch(index) {|index| ... } ⇒ Object

Tries to return the element at position index, but throws an IndexError exception if the referenced index lies outside of the array bounds. This error can be prevented by supplying a second argument, which will act as a default value.

Alternatively, if a block is given it will only be executed when an invalid index is referenced. Negative values of index count from the end of the array.

a = [ 11, 22, 33, 44 ]
a.fetch(1)               #=> 22
a.fetch(-1)              #=> 44
a.fetch(4, 'cat')        #=> "cat"
a.fetch(100) { |i| puts "#{i} is out of bounds" }
                         #=> "100 is out of bounds"

Overloads:



1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
# File 'array.c', line 1389

static VALUE
rb_ary_fetch(int argc, VALUE *argv, VALUE ary)
{
    VALUE pos, ifnone;
    long block_given;
    long idx;

    rb_scan_args(argc, argv, "11", &pos, &ifnone);
    block_given = rb_block_given_p();
    if (block_given && argc == 2) {
	rb_warn("block supersedes default value argument");
    }
    idx = NUM2LONG(pos);

    if (idx < 0) {
	idx +=  RARRAY_LEN(ary);
    }
    if (idx < 0 || RARRAY_LEN(ary) <= idx) {
	if (block_given) return rb_yield(pos);
	if (argc == 1) {
	    rb_raise(rb_eIndexError, "index %ld outside of array bounds: %ld...%ld",
			idx - (idx < 0 ? RARRAY_LEN(ary) : 0), -RARRAY_LEN(ary), RARRAY_LEN(ary));
	}
	return ifnone;
    }
    return RARRAY_AREF(ary, idx);
}

#fill(obj) ⇒ Object #fill(obj, start[, length]) ⇒ Object #fill(obj, range) ⇒ Object #fill {|index| ... } ⇒ Object #fill(start[, length]) {|index| ... } ⇒ Object #fill(range) {|index| ... } ⇒ Object

The first three forms set the selected elements of self (which may be the entire array) to obj.

A start of nil is equivalent to zero.

A length of nil is equivalent to the length of the array.

The last three forms fill the array with the value of the given block, which is passed the absolute index of each element to be filled.

Negative values of start count from the end of the array, where -1 is the last element.

a = [ "a", "b", "c", "d" ]
a.fill("x")              #=> ["x", "x", "x", "x"]
a.fill("z", 2, 2)        #=> ["x", "x", "z", "z"]
a.fill("y", 0..1)        #=> ["y", "y", "z", "z"]
a.fill { |i| i*i }       #=> [0, 1, 4, 9]
a.fill(-2) { |i| i*i*i } #=> [0, 1, 8, 27]

Overloads:

  • #fill {|index| ... } ⇒ Object

    Yields:

  • #fill(start[, length]) {|index| ... } ⇒ Object

    Yields:

  • #fill(range) {|index| ... } ⇒ Object

    Yields:



3530
3531
3532
3533
3534
3535
3536
3537
3538
3539
3540
3541
3542
3543
3544
3545
3546
3547
3548
3549
3550
3551
3552
3553
3554
3555
3556
3557
3558
3559
3560
3561
3562
3563
3564
3565
3566
3567
3568
3569
3570
3571
3572
3573
3574
3575
3576
3577
3578
3579
3580
3581
3582
3583
3584
3585
3586
3587
3588
3589
3590
3591
3592
3593
3594
# File 'array.c', line 3530

static VALUE
rb_ary_fill(int argc, VALUE *argv, VALUE ary)
{
    VALUE item, arg1, arg2;
    long beg = 0, end = 0, len = 0;
    int block_p = FALSE;

    if (rb_block_given_p()) {
	block_p = TRUE;
	rb_scan_args(argc, argv, "02", &arg1, &arg2);
	argc += 1;		/* hackish */
    }
    else {
	rb_scan_args(argc, argv, "12", &item, &arg1, &arg2);
    }
    switch (argc) {
      case 1:
	beg = 0;
	len = RARRAY_LEN(ary);
	break;
      case 2:
	if (rb_range_beg_len(arg1, &beg, &len, RARRAY_LEN(ary), 1)) {
	    break;
	}
	/* fall through */
      case 3:
	beg = NIL_P(arg1) ? 0 : NUM2LONG(arg1);
	if (beg < 0) {
	    beg = RARRAY_LEN(ary) + beg;
	    if (beg < 0) beg = 0;
	}
	len = NIL_P(arg2) ? RARRAY_LEN(ary) - beg : NUM2LONG(arg2);
	break;
    }
    rb_ary_modify(ary);
    if (len < 0) {
        return ary;
    }
    if (beg >= ARY_MAX_SIZE || len > ARY_MAX_SIZE - beg) {
	rb_raise(rb_eArgError, "argument too big");
    }
    end = beg + len;
    if (RARRAY_LEN(ary) < end) {
	if (end >= ARY_CAPA(ary)) {
	    ary_resize_capa(ary, end);
	}
	ary_mem_clear(ary, RARRAY_LEN(ary), end - RARRAY_LEN(ary));
	ARY_SET_LEN(ary, end);
    }

    if (block_p) {
	VALUE v;
	long i;

	for (i=beg; i<end; i++) {
	    v = rb_yield(LONG2NUM(i));
	    if (i>=RARRAY_LEN(ary)) break;
	    ARY_SET(ary, i, v);
	}
    }
    else {
	ary_memfill(ary, beg, len, item);
    }
    return ary;
}

#find_index(obj) ⇒ Integer? #find_index {|item| ... } ⇒ Integer? #find_indexEnumerator #index(obj) ⇒ Integer? #index {|item| ... } ⇒ Integer? #indexEnumerator

Returns the index of the first object in ary such that the object is == to obj.

If a block is given instead of an argument, returns the index of the first object for which the block returns true. Returns nil if no match is found.

See also Array#rindex.

An Enumerator is returned if neither a block nor argument is given.

a = [ "a", "b", "c" ]
a.index("b")              #=> 1
a.index("z")              #=> nil
a.index { |x| x == "b" }  #=> 1

Overloads:



1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
# File 'array.c', line 1443

static VALUE
rb_ary_index(int argc, VALUE *argv, VALUE ary)
{
    const VALUE *ptr;
    VALUE val;
    long i, len;

    if (argc == 0) {
	RETURN_ENUMERATOR(ary, 0, 0);
	for (i=0; i<RARRAY_LEN(ary); i++) {
	    if (RTEST(rb_yield(RARRAY_AREF(ary, i)))) {
		return LONG2NUM(i);
	    }
	}
	return Qnil;
    }
    rb_check_arity(argc, 0, 1);
    val = argv[0];
    if (rb_block_given_p())
	rb_warn("given block not used");
    len = RARRAY_LEN(ary);
    ptr = RARRAY_CONST_PTR(ary);
    for (i=0; i<len; i++) {
	VALUE e = ptr[i];
	switch (rb_equal_opt(e, val)) {
	  case Qundef:
	    if (!rb_equal(e, val)) break;
	  case Qtrue:
	    return LONG2NUM(i);
	  case Qfalse:
	    continue;
	}
	len = RARRAY_LEN(ary);
	ptr = RARRAY_CONST_PTR(ary);
    }
    return Qnil;
}

#firstObject? #first(n) ⇒ Object

Returns the first element, or the first n elements, of the array. If the array is empty, the first form returns nil, and the second form returns an empty array. See also Array#last for the opposite effect.

a = [ "q", "r", "s", "t" ]
a.first     #=> "q"
a.first(2)  #=> ["q", "r"]

Overloads:



1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
# File 'array.c', line 1326

static VALUE
rb_ary_first(int argc, VALUE *argv, VALUE ary)
{
    if (argc == 0) {
	if (RARRAY_LEN(ary) == 0) return Qnil;
	return RARRAY_AREF(ary, 0);
    }
    else {
	return ary_take_first_or_last(argc, argv, ary, ARY_TAKE_FIRST);
    }
}

#flattenObject #flatten(level) ⇒ Object

Returns a new array that is a one-dimensional flattening of self (recursively).

That is, for every element that is an array, extract its elements into the new array.

The optional level argument determines the level of recursion to flatten.

s = [ 1, 2, 3 ]           #=> [1, 2, 3]
t = [ 4, 5, 6, [7, 8] ]   #=> [4, 5, 6, [7, 8]]
a = [ s, t, 9, 10 ]       #=> [[1, 2, 3], [4, 5, 6, [7, 8]], 9, 10]
a.flatten                 #=> [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
a = [ 1, 2, [3, [4, 5] ] ]
a.flatten(1)              #=> [1, 2, 3, [4, 5]]


4533
4534
4535
4536
4537
4538
4539
4540
4541
4542
4543
4544
4545
4546
4547
# File 'array.c', line 4533

static VALUE
rb_ary_flatten(int argc, VALUE *argv, VALUE ary)
{
    int mod = 0, level = -1;
    VALUE result, lv;

    rb_scan_args(argc, argv, "01", &lv);
    if (!NIL_P(lv)) level = NUM2INT(lv);
    if (level == 0) return ary_make_shared_copy(ary);

    result = flatten(ary, level, &mod);
    OBJ_INFECT(result, ary);

    return result;
}

#flatten!nil #flatten!(level) ⇒ nil

Flattens self in place.

Returns nil if no modifications were made (i.e., the array contains no subarrays.)

The optional level argument determines the level of recursion to flatten.

a = [ 1, 2, [3, [4, 5] ] ]
a.flatten!   #=> [1, 2, 3, 4, 5]
a.flatten!   #=> nil
a            #=> [1, 2, 3, 4, 5]
a = [ 1, 2, [3, [4, 5] ] ]
a.flatten!(1) #=> [1, 2, 3, [4, 5]]

Overloads:

  • #flatten!nil

    Returns:

    • (nil)
  • #flatten!(level) ⇒ nil

    Returns:

    • (nil)


4488
4489
4490
4491
4492
4493
4494
4495
4496
4497
4498
4499
4500
4501
4502
4503
4504
4505
4506
4507
4508
4509
# File 'array.c', line 4488

static VALUE
rb_ary_flatten_bang(int argc, VALUE *argv, VALUE ary)
{
    int mod = 0, level = -1;
    VALUE result, lv;

    rb_scan_args(argc, argv, "01", &lv);
    rb_ary_modify_check(ary);
    if (!NIL_P(lv)) level = NUM2INT(lv);
    if (level == 0) return Qnil;

    result = flatten(ary, level, &mod);
    if (mod == 0) {
	ary_discard(result);
	return Qnil;
    }
    if (!(mod = ARY_EMBED_P(result))) rb_obj_freeze(result);
    rb_ary_replace(ary, result);
    if (mod) ARY_SET_EMBED_LEN(result, 0);

    return ary;
}

#frozen?Boolean

Return true if this array is frozen (or temporarily frozen while being sorted). See also Object#frozen?

Returns:

  • (Boolean)

Returns:

  • (Boolean)


416
417
418
419
420
421
# File 'array.c', line 416

static VALUE
rb_ary_frozen_p(VALUE ary)
{
    if (OBJ_FROZEN(ary)) return Qtrue;
    return Qfalse;
}

#hashFixnum

Compute a hash-code for this array.

Two arrays with the same content will have the same hash code (and will compare using #eql?).

See also Object#hash.

Returns:



3900
3901
3902
3903
3904
3905
3906
3907
3908
3909
3910
3911
3912
3913
3914
3915
# File 'array.c', line 3900

static VALUE
rb_ary_hash(VALUE ary)
{
    long i;
    st_index_t h;
    VALUE n;

    h = rb_hash_start(RARRAY_LEN(ary));
    h = rb_hash_uint(h, (st_index_t)rb_ary_hash);
    for (i=0; i<RARRAY_LEN(ary); i++) {
	n = rb_hash(RARRAY_AREF(ary, i));
	h = rb_hash_uint(h, NUM2LONG(n));
    }
    h = rb_hash_end(h);
    return LONG2FIX(h);
}

#include?(object) ⇒ Boolean

Returns true if the given object is present in self (that is, if any element == object), otherwise returns false.

a = [ "a", "b", "c" ]
a.include?("b")   #=> true
a.include?("z")   #=> false

Returns:

  • (Boolean)

Returns:

  • (Boolean)


3929
3930
3931
3932
3933
3934
3935
3936
3937
3938
3939
3940
3941
3942
3943
3944
3945
3946
# File 'array.c', line 3929

VALUE
rb_ary_includes(VALUE ary, VALUE item)
{
    long i;
    VALUE e;

    for (i=0; i<RARRAY_LEN(ary); i++) {
	e = RARRAY_AREF(ary, i);
	switch (rb_equal_opt(e, item)) {
	  case Qundef:
	    if (rb_equal(e, item)) return Qtrue;
	    break;
	  case Qtrue:
	    return Qtrue;
	}
    }
    return Qfalse;
}

#find_index(obj) ⇒ Integer? #find_index {|item| ... } ⇒ Integer? #find_indexEnumerator #index(obj) ⇒ Integer? #index {|item| ... } ⇒ Integer? #indexEnumerator

Returns the index of the first object in ary such that the object is == to obj.

If a block is given instead of an argument, returns the index of the first object for which the block returns true. Returns nil if no match is found.

See also Array#rindex.

An Enumerator is returned if neither a block nor argument is given.

a = [ "a", "b", "c" ]
a.index("b")              #=> 1
a.index("z")              #=> nil
a.index { |x| x == "b" }  #=> 1

Overloads:



1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
# File 'array.c', line 1443

static VALUE
rb_ary_index(int argc, VALUE *argv, VALUE ary)
{
    const VALUE *ptr;
    VALUE val;
    long i, len;

    if (argc == 0) {
	RETURN_ENUMERATOR(ary, 0, 0);
	for (i=0; i<RARRAY_LEN(ary); i++) {
	    if (RTEST(rb_yield(RARRAY_AREF(ary, i)))) {
		return LONG2NUM(i);
	    }
	}
	return Qnil;
    }
    rb_check_arity(argc, 0, 1);
    val = argv[0];
    if (rb_block_given_p())
	rb_warn("given block not used");
    len = RARRAY_LEN(ary);
    ptr = RARRAY_CONST_PTR(ary);
    for (i=0; i<len; i++) {
	VALUE e = ptr[i];
	switch (rb_equal_opt(e, val)) {
	  case Qundef:
	    if (!rb_equal(e, val)) break;
	  case Qtrue:
	    return LONG2NUM(i);
	  case Qfalse:
	    continue;
	}
	len = RARRAY_LEN(ary);
	ptr = RARRAY_CONST_PTR(ary);
    }
    return Qnil;
}

#replace(other_ary) ⇒ Object #initialize_copy(other_ary) ⇒ Object

Replaces the contents of self with the contents of other_ary, truncating or expanding if necessary.

a = [ "a", "b", "c", "d", "e" ]
a.replace([ "x", "y", "z" ])   #=> ["x", "y", "z"]
a                              #=> ["x", "y", "z"]


3433
3434
3435
3436
3437
3438
3439
3440
3441
3442
3443
3444
3445
3446
3447
3448
3449
3450
3451
3452
3453
3454
3455
3456
3457
3458
3459
3460
3461
3462
3463
3464
3465
3466
3467
3468
3469
3470
3471
# File 'array.c', line 3433

VALUE
rb_ary_replace(VALUE copy, VALUE orig)
{
    rb_ary_modify_check(copy);
    orig = to_ary(orig);
    if (copy == orig) return copy;

    if (RARRAY_LEN(orig) <= RARRAY_EMBED_LEN_MAX) {
        VALUE shared = 0;

        if (ARY_OWNS_HEAP_P(copy)) {
	    RARRAY_PTR_USE(copy, ptr, ruby_sized_xfree(ptr, ARY_HEAP_SIZE(copy)));
	}
        else if (ARY_SHARED_P(copy)) {
            shared = ARY_SHARED(copy);
            FL_UNSET_SHARED(copy);
        }
        FL_SET_EMBED(copy);
	ary_memcpy(copy, 0, RARRAY_LEN(orig), RARRAY_CONST_PTR(orig));
        if (shared) {
            rb_ary_decrement_share(shared);
        }
        ARY_SET_LEN(copy, RARRAY_LEN(orig));
    }
    else {
        VALUE shared = ary_make_shared(orig);
        if (ARY_OWNS_HEAP_P(copy)) {
	    RARRAY_PTR_USE(copy, ptr, ruby_sized_xfree(ptr, ARY_HEAP_SIZE(copy)));
        }
        else {
            rb_ary_unshare_safe(copy);
        }
        FL_UNSET_EMBED(copy);
        ARY_SET_PTR(copy, RARRAY_CONST_PTR(orig));
        ARY_SET_LEN(copy, RARRAY_LEN(orig));
        rb_ary_set_shared(copy, shared);
    }
    return copy;
}

#insert(index, obj...) ⇒ Object

Inserts the given values before the element with the given index.

Negative indices count backwards from the end of the array, where -1 is the last element. If a negative index is used, the given values will be inserted after that element, so using an index of -1 will insert the values at the end of the array.

a = %w{ a b c d }
a.insert(2, 99)         #=> ["a", "b", 99, "c", "d"]
a.insert(-2, 1, 2, 3)   #=> ["a", "b", 99, "c", 1, 2, 3, "d"]


1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
# File 'array.c', line 1762

static VALUE
rb_ary_insert(int argc, VALUE *argv, VALUE ary)
{
    long pos;

    rb_check_arity(argc, 1, UNLIMITED_ARGUMENTS);
    rb_ary_modify_check(ary);
    if (argc == 1) return ary;
    pos = NUM2LONG(argv[0]);
    if (pos == -1) {
	pos = RARRAY_LEN(ary);
    }
    if (pos < 0) {
	pos++;
    }
    rb_ary_splice(ary, pos, 0, rb_ary_new4(argc - 1, argv + 1));
    return ary;
}

#inspectString #to_sString Also known as: to_s

Creates a string representation of self.

[ "a", "b", "c" ].to_s     #=> "[\"a\", \"b\", \"c\"]"

Overloads:



2118
2119
2120
2121
2122
2123
# File 'array.c', line 2118

static VALUE
rb_ary_inspect(VALUE ary)
{
    if (RARRAY_LEN(ary) == 0) return rb_usascii_str_new2("[]");
    return rb_exec_recursive(inspect_ary, ary, 0);
}

#join(separator = $,) ⇒ String

Returns a string created by converting each element of the array to a string, separated by the given separator. If the separator is nil, it uses current $,. If both the separator and $, are nil, it uses empty string.

[ "a", "b", "c" ].join        #=> "abc"
[ "a", "b", "c" ].join("-")   #=> "a-b-c"

Returns:



2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
# File 'array.c', line 2076

static VALUE
rb_ary_join_m(int argc, VALUE *argv, VALUE ary)
{
    VALUE sep;

    rb_scan_args(argc, argv, "01", &sep);
    if (NIL_P(sep)) sep = rb_output_fs;

    return rb_ary_join(ary, sep);
}

#keep_if {|item| ... } ⇒ Object #keep_ifEnumerator

Deletes every element of self for which the given block evaluates to false.

See also Array#select!

If no block is given, an Enumerator is returned instead.

a = %w{ a b c d e f }
a.keep_if { |v| v =~ /[aeiou]/ }  #=> ["a", "e"]

Overloads:



2947
2948
2949
2950
2951
2952
2953
# File 'array.c', line 2947

static VALUE
rb_ary_keep_if(VALUE ary)
{
    RETURN_SIZED_ENUMERATOR(ary, 0, 0, ary_enum_length);
    rb_ary_select_bang(ary);
    return ary;
}

#lastObject? #last(n) ⇒ Object

Returns the last element(s) of self. If the array is empty, the first form returns nil.

See also Array#first for the opposite effect.

a = [ "w", "x", "y", "z" ]
a.last     #=> "z"
a.last(2)  #=> ["y", "z"]

Overloads:



1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
# File 'array.c', line 1353

VALUE
rb_ary_last(int argc, const VALUE *argv, VALUE ary)
{
    if (argc == 0) {
	long len = RARRAY_LEN(ary);
	if (len == 0) return Qnil;
	return RARRAY_AREF(ary, len-1);
    }
    else {
	return ary_take_first_or_last(argc, argv, ary, ARY_TAKE_LAST);
    }
}

#lengthInteger Also known as: size

Returns the number of elements in self. May be zero.

[ 1, 2, 3, 4, 5 ].length   #=> 5
[].length                  #=> 0

Returns:



1893
1894
1895
1896
1897
1898
# File 'array.c', line 1893

static VALUE
rb_ary_length(VALUE ary)
{
    long len = RARRAY_LEN(ary);
    return LONG2NUM(len);
}

#collect {|item| ... } ⇒ Object #map {|item| ... } ⇒ Object #collectEnumerator #mapEnumerator

Invokes the given block once for each element of self.

Creates a new array containing the values returned by the block.

See also Enumerable#collect.

If no block is given, an Enumerator is returned instead.

a = [ "a", "b", "c", "d" ]
a.collect { |x| x + "!" }         #=> ["a!", "b!", "c!", "d!"]
a.map.with_index { |x, i| x * i } #=> ["", "b", "cc", "ddd"]
a                                 #=> ["a", "b", "c", "d"]

Overloads:



2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
# File 'array.c', line 2724

static VALUE
rb_ary_collect(VALUE ary)
{
    long i;
    VALUE collect;

    RETURN_SIZED_ENUMERATOR(ary, 0, 0, ary_enum_length);
    collect = rb_ary_new2(RARRAY_LEN(ary));
    for (i = 0; i < RARRAY_LEN(ary); i++) {
	rb_ary_push(collect, rb_yield(RARRAY_AREF(ary, i)));
    }
    return collect;
}

#collect! {|item| ... } ⇒ Object #map! {|item| ... } ⇒ Object #collect!Enumerator #map!Enumerator

Invokes the given block once for each element of self, replacing the element with the value returned by the block.

See also Enumerable#collect.

If no block is given, an Enumerator is returned instead.

a = [ "a", "b", "c", "d" ]
a.map! {|x| x + "!" }
a #=>  [ "a!", "b!", "c!", "d!" ]
a.collect!.with_index {|x, i| x[0...i] }
a #=>  ["", "b", "c!", "d!"]

Overloads:



2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
# File 'array.c', line 2760

static VALUE
rb_ary_collect_bang(VALUE ary)
{
    long i;

    RETURN_SIZED_ENUMERATOR(ary, 0, 0, ary_enum_length);
    rb_ary_modify(ary);
    for (i = 0; i < RARRAY_LEN(ary); i++) {
	rb_ary_store(ary, i, rb_yield(RARRAY_AREF(ary, i)));
    }
    return ary;
}

#pack(fmt) ⇒ Object

Packs the contents of arr into a binary sequence according to the directives in aTemplateString (see the table below) Directives “A,'' “a,'' and “Z'' may be followed by a count, which gives the width of the resulting field. The remaining directives also may take a count, indicating the number of array elements to convert. If the count is an asterisk (“*''), all remaining array elements will be converted. Any of the directives “sSiIlL'' may be followed by an underscore (“_'') or exclamation mark (“!'') to use the underlying platform's native size for the specified type; otherwise, they use a platform-independent size. Spaces are ignored in the template string. See also String#unpack.

a = [ "a", "b", "c" ]
n = [ 65, 66, 67 ]
a.pack("A3A3A3")   #=> "a  b  c  "
a.pack("a3a3a3")   #=> "a\000\000b\000\000c\000\000"
n.pack("ccc")      #=> "ABC"

Directives for pack.

Integer      | Array   |
Directive    | Element | Meaning
---------------------------------------------------------------------------
   C         | Integer | 8-bit unsigned (unsigned char)
   S         | Integer | 16-bit unsigned, native endian (uint16_t)
   L         | Integer | 32-bit unsigned, native endian (uint32_t)
   Q         | Integer | 64-bit unsigned, native endian (uint64_t)
   J         | Integer | pointer width unsigned, native endian (uintptr_t)
             |         | (J is available since Ruby 2.3.)
             |         |
   c         | Integer | 8-bit signed (signed char)
   s         | Integer | 16-bit signed, native endian (int16_t)
   l         | Integer | 32-bit signed, native endian (int32_t)
   q         | Integer | 64-bit signed, native endian (int64_t)
   j         | Integer | pointer width signed, native endian (intptr_t)
             |         | (j is available since Ruby 2.3.)
             |         |
   S_, S!    | Integer | unsigned short, native endian
   I, I_, I! | Integer | unsigned int, native endian
   L_, L!    | Integer | unsigned long, native endian
   Q_, Q!    | Integer | unsigned long long, native endian (ArgumentError
             |         | if the platform has no long long type.)
             |         | (Q_ and Q! is available since Ruby 2.1.)
   J!        | Integer | uintptr_t, native endian (same with J)
             |         | (J! is available since Ruby 2.3.)
             |         |
   s_, s!    | Integer | signed short, native endian
   i, i_, i! | Integer | signed int, native endian
   l_, l!    | Integer | signed long, native endian
   q_, q!    | Integer | signed long long, native endian (ArgumentError
             |         | if the platform has no long long type.)
             |         | (q_ and q! is available since Ruby 2.1.)
   j!        | Integer | intptr_t, native endian (same with j)
             |         | (j! is available since Ruby 2.3.)
             |         |
   S> L> Q>  | Integer | same as the directives without ">" except
   J> s> l>  |         | big endian
   q> j>     |         | (available since Ruby 1.9.3)
   S!> I!>   |         | "S>" is same as "n"
   L!> Q!>   |         | "L>" is same as "N"
   J!> s!>   |         |
   i!> l!>   |         |
   q!> j!>   |         |
             |         |
   S< L< Q<  | Integer | same as the directives without "<" except
   J< s< l<  |         | little endian
   q< j<     |         | (available since Ruby 1.9.3)
   S!< I!<   |         | "S<" is same as "v"
   L!< Q!<   |         | "L<" is same as "V"
   J!< s!<   |         |
   i!< l!<   |         |
   q!< j!<   |         |
             |         |
   n         | Integer | 16-bit unsigned, network (big-endian) byte order
   N         | Integer | 32-bit unsigned, network (big-endian) byte order
   v         | Integer | 16-bit unsigned, VAX (little-endian) byte order
   V         | Integer | 32-bit unsigned, VAX (little-endian) byte order
             |         |
   U         | Integer | UTF-8 character
   w         | Integer | BER-compressed integer

Float        |         |
Directive    |         | Meaning
---------------------------------------------------------------------------
   D, d      | Float   | double-precision, native format
   F, f      | Float   | single-precision, native format
   E         | Float   | double-precision, little-endian byte order
   e         | Float   | single-precision, little-endian byte order
   G         | Float   | double-precision, network (big-endian) byte order
   g         | Float   | single-precision, network (big-endian) byte order

String       |         |
Directive    |         | Meaning
---------------------------------------------------------------------------
   A         | String  | arbitrary binary string (space padded, count is width)
   a         | String  | arbitrary binary string (null padded, count is width)
   Z         | String  | same as ``a'', except that null is added with *
   B         | String  | bit string (MSB first)
   b         | String  | bit string (LSB first)
   H         | String  | hex string (high nibble first)
   h         | String  | hex string (low nibble first)
   u         | String  | UU-encoded string
   M         | String  | quoted printable, MIME encoding (see RFC2045)
   m         | String  | base64 encoded string (see RFC 2045, count is width)
             |         | (if count is 0, no line feed are added, see RFC 4648)
   P         | String  | pointer to a structure (fixed-length string)
   p         | String  | pointer to a null-terminated string

Misc.        |         |
Directive    |         | Meaning
---------------------------------------------------------------------------
   @         | ---     | moves to absolute position
   X         | ---     | back up a byte
   x         | ---     | null byte


356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
# File 'pack.c', line 356

static VALUE
pack_pack(VALUE ary, VALUE fmt)
{
    static const char nul10[] = "\0\0\0\0\0\0\0\0\0\0";
    static const char spc10[] = "          ";
    const char *p, *pend;
    VALUE res, from, associates = 0;
    char type;
    long len, idx, plen;
    const char *ptr;
    int enc_info = 1;		/* 0 - BINARY, 1 - US-ASCII, 2 - UTF-8 */
#ifdef NATINT_PACK
    int natint;		/* native integer */
#endif
    int integer_size, bigendian_p;

    StringValue(fmt);
    p = RSTRING_PTR(fmt);
    pend = p + RSTRING_LEN(fmt);
    res = rb_str_buf_new(0);

    idx = 0;

#define TOO_FEW (rb_raise(rb_eArgError, toofew), 0)
#define MORE_ITEM (idx < RARRAY_LEN(ary))
#define THISFROM (MORE_ITEM ? RARRAY_AREF(ary, idx) : TOO_FEW)
#define NEXTFROM (MORE_ITEM ? RARRAY_AREF(ary, idx++) : TOO_FEW)

    while (p < pend) {
	int explicit_endian = 0;
	if (RSTRING_PTR(fmt) + RSTRING_LEN(fmt) != pend) {
	    rb_raise(rb_eRuntimeError, "format string modified");
	}
	type = *p++;		/* get data type */
#ifdef NATINT_PACK
	natint = 0;
#endif

	if (ISSPACE(type)) continue;
	if (type == '#') {
	    while ((p < pend) && (*p != '\n')) {
		p++;
	    }
	    continue;
	}

	{
          modifiers:
	    switch (*p) {
	      case '_':
	      case '!':
		if (strchr(natstr, type)) {
#ifdef NATINT_PACK
		    natint = 1;
#endif
		    p++;
		}
		else {
		    rb_raise(rb_eArgError, "'%c' allowed only after types %s", *p, natstr);
		}
		goto modifiers;

	      case '<':
	      case '>':
		if (!strchr(endstr, type)) {
		    rb_raise(rb_eArgError, "'%c' allowed only after types %s", *p, endstr);
		}
		if (explicit_endian) {
		    rb_raise(rb_eRangeError, "Can't use both '<' and '>'");
		}
		explicit_endian = *p++;
		goto modifiers;
	    }
	}

	if (*p == '*') {	/* set data length */
	    len = strchr("@Xxu", type) ? 0
                : strchr("PMm", type) ? 1
                : RARRAY_LEN(ary) - idx;
	    p++;
	}
	else if (ISDIGIT(*p)) {
	    errno = 0;
	    len = STRTOUL(p, (char**)&p, 10);
	    if (errno) {
		rb_raise(rb_eRangeError, "pack length too big");
	    }
	}
	else {
	    len = 1;
	}

	switch (type) {
	  case 'U':
	    /* if encoding is US-ASCII, upgrade to UTF-8 */
	    if (enc_info == 1) enc_info = 2;
	    break;
	  case 'm': case 'M': case 'u':
	    /* keep US-ASCII (do nothing) */
	    break;
	  default:
	    /* fall back to BINARY */
	    enc_info = 0;
	    break;
	}
	switch (type) {
	  case 'A': case 'a': case 'Z':
	  case 'B': case 'b':
	  case 'H': case 'h':
	    from = NEXTFROM;
	    if (NIL_P(from)) {
		ptr = "";
		plen = 0;
	    }
	    else {
		StringValue(from);
		ptr = RSTRING_PTR(from);
		plen = RSTRING_LEN(from);
		OBJ_INFECT(res, from);
	    }

	    if (p[-1] == '*')
		len = plen;

	    switch (type) {
	      case 'a':		/* arbitrary binary string (null padded)  */
	      case 'A':         /* arbitrary binary string (ASCII space padded) */
	      case 'Z':         /* null terminated string  */
		if (plen >= len) {
		    rb_str_buf_cat(res, ptr, len);
		    if (p[-1] == '*' && type == 'Z')
			rb_str_buf_cat(res, nul10, 1);
		}
		else {
		    rb_str_buf_cat(res, ptr, plen);
		    len -= plen;
		    while (len >= 10) {
			rb_str_buf_cat(res, (type == 'A')?spc10:nul10, 10);
			len -= 10;
		    }
		    rb_str_buf_cat(res, (type == 'A')?spc10:nul10, len);
		}
		break;

#define castchar(from) (char)((from) & 0xff)

	      case 'b':		/* bit string (ascending) */
		{
		    int byte = 0;
		    long i, j = 0;

		    if (len > plen) {
			j = (len - plen + 1)/2;
			len = plen;
		    }
		    for (i=0; i++ < len; ptr++) {
			if (*ptr & 1)
			    byte |= 128;
			if (i & 7)
			    byte >>= 1;
			else {
			    char c = castchar(byte);
			    rb_str_buf_cat(res, &c, 1);
			    byte = 0;
			}
		    }
		    if (len & 7) {
			char c;
			byte >>= 7 - (len & 7);
			c = castchar(byte);
			rb_str_buf_cat(res, &c, 1);
		    }
		    len = j;
		    goto grow;
		}
		break;

	      case 'B':		/* bit string (descending) */
		{
		    int byte = 0;
		    long i, j = 0;

		    if (len > plen) {
			j = (len - plen + 1)/2;
			len = plen;
		    }
		    for (i=0; i++ < len; ptr++) {
			byte |= *ptr & 1;
			if (i & 7)
			    byte <<= 1;
			else {
			    char c = castchar(byte);
			    rb_str_buf_cat(res, &c, 1);
			    byte = 0;
			}
		    }
		    if (len & 7) {
			char c;
			byte <<= 7 - (len & 7);
			c = castchar(byte);
			rb_str_buf_cat(res, &c, 1);
		    }
		    len = j;
		    goto grow;
		}
		break;

	      case 'h':		/* hex string (low nibble first) */
		{
		    int byte = 0;
		    long i, j = 0;

		    if (len > plen) {
			j = (len + 1) / 2 - (plen + 1) / 2;
			len = plen;
		    }
		    for (i=0; i++ < len; ptr++) {
			if (ISALPHA(*ptr))
			    byte |= (((*ptr & 15) + 9) & 15) << 4;
			else
			    byte |= (*ptr & 15) << 4;
			if (i & 1)
			    byte >>= 4;
			else {
			    char c = castchar(byte);
			    rb_str_buf_cat(res, &c, 1);
			    byte = 0;
			}
		    }
		    if (len & 1) {
			char c = castchar(byte);
			rb_str_buf_cat(res, &c, 1);
		    }
		    len = j;
		    goto grow;
		}
		break;

	      case 'H':		/* hex string (high nibble first) */
		{
		    int byte = 0;
		    long i, j = 0;

		    if (len > plen) {
			j = (len + 1) / 2 - (plen + 1) / 2;
			len = plen;
		    }
		    for (i=0; i++ < len; ptr++) {
			if (ISALPHA(*ptr))
			    byte |= ((*ptr & 15) + 9) & 15;
			else
			    byte |= *ptr & 15;
			if (i & 1)
			    byte <<= 4;
			else {
			    char c = castchar(byte);
			    rb_str_buf_cat(res, &c, 1);
			    byte = 0;
			}
		    }
		    if (len & 1) {
			char c = castchar(byte);
			rb_str_buf_cat(res, &c, 1);
		    }
		    len = j;
		    goto grow;
		}
		break;
	    }
	    break;

	  case 'c':		/* signed char */
	  case 'C':		/* unsigned char */
            integer_size = 1;
            bigendian_p = BIGENDIAN_P(); /* not effective */
            goto pack_integer;

	  case 's':		/* s for int16_t, s! for signed short */
            integer_size = NATINT_LEN(short, 2);
            bigendian_p = BIGENDIAN_P();
            goto pack_integer;

	  case 'S':		/* S for uint16_t, S! for unsigned short */
            integer_size = NATINT_LEN(short, 2);
            bigendian_p = BIGENDIAN_P();
            goto pack_integer;

	  case 'i':		/* i and i! for signed int */
            integer_size = (int)sizeof(int);
            bigendian_p = BIGENDIAN_P();
            goto pack_integer;

	  case 'I':		/* I and I! for unsigned int */
            integer_size = (int)sizeof(int);
            bigendian_p = BIGENDIAN_P();
            goto pack_integer;

	  case 'l':		/* l for int32_t, l! for signed long */
            integer_size = NATINT_LEN(long, 4);
            bigendian_p = BIGENDIAN_P();
            goto pack_integer;

	  case 'L':		/* L for uint32_t, L! for unsigned long */
            integer_size = NATINT_LEN(long, 4);
            bigendian_p = BIGENDIAN_P();
            goto pack_integer;

	  case 'q':		/* q for int64_t, q! for signed long long */
	    integer_size = NATINT_LEN_Q;
            bigendian_p = BIGENDIAN_P();
            goto pack_integer;

	  case 'Q':		/* Q for uint64_t, Q! for unsigned long long */
	    integer_size = NATINT_LEN_Q;
            bigendian_p = BIGENDIAN_P();
            goto pack_integer;

	  case 'j':		/* j for intptr_t */
	    integer_size = sizeof(intptr_t);
	    bigendian_p = BIGENDIAN_P();
	    goto pack_integer;

	  case 'J':		/* J for uintptr_t */
	    integer_size = sizeof(uintptr_t);
	    bigendian_p = BIGENDIAN_P();
	    goto pack_integer;

	  case 'n':		/* 16 bit (2 bytes) integer (network byte-order)  */
            integer_size = 2;
            bigendian_p = 1;
            goto pack_integer;

	  case 'N':		/* 32 bit (4 bytes) integer (network byte-order) */
            integer_size = 4;
            bigendian_p = 1;
            goto pack_integer;

	  case 'v':		/* 16 bit (2 bytes) integer (VAX byte-order) */
            integer_size = 2;
            bigendian_p = 0;
            goto pack_integer;

	  case 'V':		/* 32 bit (4 bytes) integer (VAX byte-order) */
            integer_size = 4;
            bigendian_p = 0;
            goto pack_integer;

          pack_integer:
	    if (explicit_endian) {
		bigendian_p = explicit_endian == '>';
	    }
            if (integer_size > MAX_INTEGER_PACK_SIZE)
                rb_bug("unexpected intger size for pack: %d", integer_size);
            while (len-- > 0) {
                char intbuf[MAX_INTEGER_PACK_SIZE];

                from = NEXTFROM;
                rb_integer_pack(from, intbuf, integer_size, 1, 0,
                    INTEGER_PACK_2COMP |
                    (bigendian_p ? INTEGER_PACK_BIG_ENDIAN : INTEGER_PACK_LITTLE_ENDIAN));
                rb_str_buf_cat(res, intbuf, integer_size);
            }
	    break;

	  case 'f':		/* single precision float in native format */
	  case 'F':		/* ditto */
	    while (len-- > 0) {
		float f;

		from = NEXTFROM;
		f = (float)RFLOAT_VALUE(rb_to_float(from));
		rb_str_buf_cat(res, (char*)&f, sizeof(float));
	    }
	    break;

	  case 'e':		/* single precision float in VAX byte-order */
	    while (len-- > 0) {
		float f;
		FLOAT_CONVWITH(ftmp);

		from = NEXTFROM;
		f = (float)RFLOAT_VALUE(rb_to_float(from));
		f = HTOVF(f,ftmp);
		rb_str_buf_cat(res, (char*)&f, sizeof(float));
	    }
	    break;

	  case 'E':		/* double precision float in VAX byte-order */
	    while (len-- > 0) {
		double d;
		DOUBLE_CONVWITH(dtmp);

		from = NEXTFROM;
		d = RFLOAT_VALUE(rb_to_float(from));
		d = HTOVD(d,dtmp);
		rb_str_buf_cat(res, (char*)&d, sizeof(double));
	    }
	    break;

	  case 'd':		/* double precision float in native format */
	  case 'D':		/* ditto */
	    while (len-- > 0) {
		double d;

		from = NEXTFROM;
		d = RFLOAT_VALUE(rb_to_float(from));
		rb_str_buf_cat(res, (char*)&d, sizeof(double));
	    }
	    break;

	  case 'g':		/* single precision float in network byte-order */
	    while (len-- > 0) {
		float f;
		FLOAT_CONVWITH(ftmp);

		from = NEXTFROM;
		f = (float)RFLOAT_VALUE(rb_to_float(from));
		f = HTONF(f,ftmp);
		rb_str_buf_cat(res, (char*)&f, sizeof(float));
	    }
	    break;

	  case 'G':		/* double precision float in network byte-order */
	    while (len-- > 0) {
		double d;
		DOUBLE_CONVWITH(dtmp);

		from = NEXTFROM;
		d = RFLOAT_VALUE(rb_to_float(from));
		d = HTOND(d,dtmp);
		rb_str_buf_cat(res, (char*)&d, sizeof(double));
	    }
	    break;

	  case 'x':		/* null byte */
	  grow:
	    while (len >= 10) {
		rb_str_buf_cat(res, nul10, 10);
		len -= 10;
	    }
	    rb_str_buf_cat(res, nul10, len);
	    break;

	  case 'X':		/* back up byte */
	  shrink:
	    plen = RSTRING_LEN(res);
	    if (plen < len)
		rb_raise(rb_eArgError, "X outside of string");
	    rb_str_set_len(res, plen - len);
	    break;

	  case '@':		/* null fill to absolute position */
	    len -= RSTRING_LEN(res);
	    if (len > 0) goto grow;
	    len = -len;
	    if (len > 0) goto shrink;
	    break;

	  case '%':
	    rb_raise(rb_eArgError, "%% is not supported");
	    break;

	  case 'U':		/* Unicode character */
	    while (len-- > 0) {
		SIGNED_VALUE l;
		char buf[8];
		int le;

		from = NEXTFROM;
		from = rb_to_int(from);
		l = NUM2LONG(from);
		if (l < 0) {
		    rb_raise(rb_eRangeError, "pack(U): value out of range");
		}
		le = rb_uv_to_utf8(buf, l);
		rb_str_buf_cat(res, (char*)buf, le);
	    }
	    break;

	  case 'u':		/* uuencoded string */
	  case 'm':		/* base64 encoded string */
	    from = NEXTFROM;
	    StringValue(from);
	    ptr = RSTRING_PTR(from);
	    plen = RSTRING_LEN(from);

	    if (len == 0 && type == 'm') {
		encodes(res, ptr, plen, type, 0);
		ptr += plen;
		break;
	    }
	    if (len <= 2)
		len = 45;
	    else if (len > 63 && type == 'u')
		len = 63;
	    else
		len = len / 3 * 3;
	    while (plen > 0) {
		long todo;

		if (plen > len)
		    todo = len;
		else
		    todo = plen;
		encodes(res, ptr, todo, type, 1);
		plen -= todo;
		ptr += todo;
	    }
	    break;

	  case 'M':		/* quoted-printable encoded string */
	    from = rb_obj_as_string(NEXTFROM);
	    if (len <= 1)
		len = 72;
	    qpencode(res, from, len);
	    break;

	  case 'P':		/* pointer to packed byte string */
	    from = THISFROM;
	    if (!NIL_P(from)) {
		StringValue(from);
		if (RSTRING_LEN(from) < len) {
		    rb_raise(rb_eArgError, "too short buffer for P(%ld for %ld)",
			     RSTRING_LEN(from), len);
		}
	    }
	    len = 1;
	    /* FALL THROUGH */
	  case 'p':		/* pointer to string */
	    while (len-- > 0) {
		char *t;
		from = NEXTFROM;
		if (NIL_P(from)) {
		    t = 0;
		}
		else {
		    t = StringValuePtr(from);
		    rb_obj_taint(from);
		}
		if (!associates) {
		    associates = rb_ary_new();
		}
		rb_ary_push(associates, from);
		rb_str_buf_cat(res, (char*)&t, sizeof(char*));
	    }
	    break;

	  case 'w':		/* BER compressed integer  */
	    while (len-- > 0) {
		VALUE buf = rb_str_new(0, 0);
                size_t numbytes;
                int sign;
                char *cp;

		from = NEXTFROM;
                from = rb_to_int(from);
                numbytes = rb_absint_numwords(from, 7, NULL);
                if (numbytes == 0)
                    numbytes = 1;
                buf = rb_str_new(NULL, numbytes);

                sign = rb_integer_pack(from, RSTRING_PTR(buf), RSTRING_LEN(buf), 1, 1, INTEGER_PACK_BIG_ENDIAN);

                if (sign < 0)
                    rb_raise(rb_eArgError, "can't compress negative numbers");
                if (sign == 2)
                    rb_bug("buffer size problem?");

                cp = RSTRING_PTR(buf);
                while (1 < numbytes) {
                  *cp |= 0x80;
                  cp++;
                  numbytes--;
                }

                rb_str_buf_cat(res, RSTRING_PTR(buf), RSTRING_LEN(buf));
	    }
	    break;

	  default: {
	    char unknown[5];
	    if (ISPRINT(type)) {
		unknown[0] = type;
		unknown[1] = '\0';
	    }
	    else {
		snprintf(unknown, sizeof(unknown), "\\x%.2x", type & 0xff);
	    }
	    rb_warning("unknown pack directive '%s' in '% "PRIsVALUE"'",
		       unknown, fmt);
	    break;
	  }
	}
    }

    if (associates) {
	str_associate(res, associates);
    }
    OBJ_INFECT(res, fmt);
    switch (enc_info) {
      case 1:
	ENCODING_CODERANGE_SET(res, rb_usascii_encindex(), ENC_CODERANGE_7BIT);
	break;
      case 2:
	rb_enc_set_index(res, rb_utf8_encindex());
	break;
      default:
	/* do nothing, keep ASCII-8BIT */
	break;
    }
    return res;
}

#permutation {|p| ... } ⇒ Object #permutationEnumerator #permutation(n) {|p| ... } ⇒ Object #permutation(n) ⇒ Enumerator

When invoked with a block, yield all permutations of length n of the elements of the array, then return the array itself.

If n is not specified, yield all permutations of all elements.

The implementation makes no guarantees about the order in which the permutations are yielded.

If no block is given, an Enumerator is returned instead.

Examples:

a = [1, 2, 3]
a.permutation.to_a    #=> [[1,2,3],[1,3,2],[2,1,3],[2,3,1],[3,1,2],[3,2,1]]
a.permutation(1).to_a #=> [[1],[2],[3]]
a.permutation(2).to_a #=> [[1,2],[1,3],[2,1],[2,3],[3,1],[3,2]]
a.permutation(3).to_a #=> [[1,2,3],[1,3,2],[2,1,3],[2,3,1],[3,1,2],[3,2,1]]
a.permutation(0).to_a #=> [[]] # one permutation of length 0
a.permutation(4).to_a #=> []   # no permutations of length 4

Overloads:



4958
4959
4960
4961
4962
4963
4964
4965
4966
4967
4968
4969
4970
4971
4972
4973
4974
4975
4976
4977
4978
4979
4980
4981
4982
4983
4984
4985
4986
4987
4988
4989
4990
4991
4992
4993
4994
# File 'array.c', line 4958

static VALUE
rb_ary_permutation(int argc, VALUE *argv, VALUE ary)
{
    VALUE num;
    long r, n, i;

    n = RARRAY_LEN(ary);                  /* Array length */
    RETURN_SIZED_ENUMERATOR(ary, argc, argv, rb_ary_permutation_size);   /* Return enumerator if no block */
    rb_scan_args(argc, argv, "01", &num);
    r = NIL_P(num) ? n : NUM2LONG(num);   /* Permutation size from argument */

    if (r < 0 || n < r) {
	/* no permutations: yield nothing */
    }
    else if (r == 0) { /* exactly one permutation: the zero-length array */
	rb_yield(rb_ary_new2(0));
    }
    else if (r == 1) { /* this is a special, easy case */
	for (i = 0; i < RARRAY_LEN(ary); i++) {
	    rb_yield(rb_ary_new3(1, RARRAY_AREF(ary, i)));
	}
    }
    else {             /* this is the general case */
	volatile VALUE t0;
	long *p = ALLOCV_N(long, t0, r+roomof(n, sizeof(long)));
	char *used = (char*)(p + r);
	VALUE ary0 = ary_make_shared_copy(ary); /* private defensive copy of ary */
	RBASIC_CLEAR_CLASS(ary0);

	MEMZERO(used, char, n); /* initialize array */

	permute0(n, r, p, used, ary0); /* compute and yield permutations */
	ALLOCV_END(t0);
	RBASIC_SET_CLASS_RAW(ary0, rb_cArray);
    }
    return ary;
}

#popObject? #pop(n) ⇒ Object

Removes the last element from self and returns it, or nil if the array is empty.

If a number n is given, returns an array of the last n elements (or less) just like array.slice!(-n, n) does. See also Array#push for the opposite effect.

a = [ "a", "b", "c", "d" ]
a.pop     #=> "d"
a.pop(2)  #=> ["b", "c"]
a         #=> ["a"]

Overloads:



984
985
986
987
988
989
990
991
992
993
994
995
996
997
# File 'array.c', line 984

static VALUE
rb_ary_pop_m(int argc, VALUE *argv, VALUE ary)
{
    VALUE result;

    if (argc == 0) {
	return rb_ary_pop(ary);
    }

    rb_ary_modify_check(ary);
    result = ary_take_first_or_last(argc, argv, ary, ARY_TAKE_LAST);
    ARY_INCREASE_LEN(ary, -RARRAY_LEN(result));
    return result;
}

#product(other_ary, ...) ⇒ Object #product(other_ary, ...) {|p| ... } ⇒ Object

Returns an array of all combinations of elements from all arrays.

The length of the returned array is the product of the length of self and the argument arrays.

If given a block, #product will yield all combinations and return self instead.

[1,2,3].product([4,5])     #=> [[1,4],[1,5],[2,4],[2,5],[3,4],[3,5]]
[1,2].product([1,2])       #=> [[1,1],[1,2],[2,1],[2,2]]
[1,2].product([3,4],[5,6]) #=> [[1,3,5],[1,3,6],[1,4,5],[1,4,6],
                           #     [2,3,5],[2,3,6],[2,4,5],[2,4,6]]
[1,2].product()            #=> [[1],[2]]
[1,2].product([])          #=> []

Overloads:

  • #product(other_ary, ...) {|p| ... } ⇒ Object

    Yields:

    • (p)


5306
5307
5308
5309
5310
5311
5312
5313
5314
5315
5316
5317
5318
5319
5320
5321
5322
5323
5324
5325
5326
5327
5328
5329
5330
5331
5332
5333
5334
5335
5336
5337
5338
5339
5340
5341
5342
5343
5344
5345
5346
5347
5348
5349
5350
5351
5352
5353
5354
5355
5356
5357
5358
5359
5360
5361
5362
5363
5364
5365
5366
5367
5368
5369
5370
5371
5372
5373
5374
5375
5376
5377
5378
5379
5380
5381
5382
5383
5384
5385
5386
5387
5388
5389
5390
5391
5392
5393
# File 'array.c', line 5306

static VALUE
rb_ary_product(int argc, VALUE *argv, VALUE ary)
{
    int n = argc+1;    /* How many arrays we're operating on */
    volatile VALUE t0 = tmpary(n);
    volatile VALUE t1 = tmpbuf(n, sizeof(int));
    VALUE *arrays = RARRAY_PTR(t0); /* The arrays we're computing the product of */
    int *counters = (int*)RSTRING_PTR(t1); /* The current position in each one */
    VALUE result = Qnil;      /* The array we'll be returning, when no block given */
    long i,j;
    long resultlen = 1;

    RBASIC_CLEAR_CLASS(t0);
    RBASIC_CLEAR_CLASS(t1);

    /* initialize the arrays of arrays */
    ARY_SET_LEN(t0, n);
    arrays[0] = ary;
    for (i = 1; i < n; i++) arrays[i] = Qnil;
    for (i = 1; i < n; i++) arrays[i] = to_ary(argv[i-1]);

    /* initialize the counters for the arrays */
    for (i = 0; i < n; i++) counters[i] = 0;

    /* Otherwise, allocate and fill in an array of results */
    if (rb_block_given_p()) {
	/* Make defensive copies of arrays; exit if any is empty */
	for (i = 0; i < n; i++) {
	    if (RARRAY_LEN(arrays[i]) == 0) goto done;
	    arrays[i] = ary_make_shared_copy(arrays[i]);
	}
    }
    else {
	/* Compute the length of the result array; return [] if any is empty */
	for (i = 0; i < n; i++) {
	    long k = RARRAY_LEN(arrays[i]);
	    if (k == 0) {
		result = rb_ary_new2(0);
		goto done;
	    }
            if (MUL_OVERFLOW_LONG_P(resultlen, k))
		rb_raise(rb_eRangeError, "too big to product");
	    resultlen *= k;
	}
	result = rb_ary_new2(resultlen);
    }
    for (;;) {
	int m;
	/* fill in one subarray */
	VALUE subarray = rb_ary_new2(n);
	for (j = 0; j < n; j++) {
	    rb_ary_push(subarray, rb_ary_entry(arrays[j], counters[j]));
	}

	/* put it on the result array */
	if (NIL_P(result)) {
	    FL_SET(t0, FL_USER5);
	    rb_yield(subarray);
	    if (! FL_TEST(t0, FL_USER5)) {
		rb_raise(rb_eRuntimeError, "product reentered");
	    }
	    else {
		FL_UNSET(t0, FL_USER5);
	    }
	}
	else {
	    rb_ary_push(result, subarray);
	}

	/*
	 * Increment the last counter.  If it overflows, reset to 0
	 * and increment the one before it.
	 */
	m = n-1;
	counters[m]++;
	while (counters[m] == RARRAY_LEN(arrays[m])) {
	    counters[m] = 0;
	    /* If the first counter overflows, we are done */
	    if (--m < 0) goto done;
	    counters[m]++;
	}
    }
done:
    tmpary_discard(t0);
    tmpbuf_discard(t1);

    return NIL_P(result) ? ary : result;
}

#push(obj, ...) ⇒ Object

Append — Pushes the given object(s) on to the end of this array. This expression returns the array itself, so several appends may be chained together. See also Array#pop for the opposite effect.

a = [ "a", "b", "c" ]
a.push("d", "e", "f")
        #=> ["a", "b", "c", "d", "e", "f"]
[1, 2, 3,].push(4).push(5)
        #=> [1, 2, 3, 4, 5]


942
943
944
945
946
# File 'array.c', line 942

static VALUE
rb_ary_push_m(int argc, VALUE *argv, VALUE ary)
{
    return rb_ary_cat(ary, argv, argc);
}

#rassoc(obj) ⇒ nil

Searches through the array whose elements are also arrays.

Compares obj with the second element of each contained array using obj.==.

Returns the first contained array that matches obj.

See also Array#assoc.

a = [ [ 1, "one"], [2, "two"], [3, "three"], ["ii", "two"] ]
a.rassoc("two")    #=> [2, "two"]
a.rassoc("four")   #=> nil

Returns:

  • (nil)


3779
3780
3781
3782
3783
3784
3785
3786
3787
3788
3789
3790
3791
3792
3793
# File 'array.c', line 3779

VALUE
rb_ary_rassoc(VALUE ary, VALUE value)
{
    long i;
    VALUE v;

    for (i = 0; i < RARRAY_LEN(ary); ++i) {
	v = RARRAY_AREF(ary, i);
	if (RB_TYPE_P(v, T_ARRAY) &&
	    RARRAY_LEN(v) > 1 &&
	    rb_equal(RARRAY_AREF(v, 1), value))
	    return v;
    }
    return Qnil;
}

#reject {|item| ... } ⇒ Object #rejectEnumerator

Returns a new array containing the items in self for which the given block is not true. The ordering of non-rejected elements is maintained.

See also Array#delete_if

If no block is given, an Enumerator is returned instead.

Overloads:



3234
3235
3236
3237
3238
3239
3240
3241
3242
3243
# File 'array.c', line 3234

static VALUE
rb_ary_reject(VALUE ary)
{
    VALUE rejected_ary;

    RETURN_SIZED_ENUMERATOR(ary, 0, 0, ary_enum_length);
    rejected_ary = rb_ary_new();
    ary_reject(ary, rejected_ary);
    return rejected_ary;
}

#reject! {|item| ... } ⇒ nil #reject!Enumerator

Deletes every element of self for which the block evaluates to true, if no changes were made returns nil.

The array may not be changed instantly every time the block is called.

See also Enumerable#reject and Array#delete_if.

If no block is given, an Enumerator is returned instead.

Overloads:

  • #reject! {|item| ... } ⇒ nil

    Yields:

    • (item)

    Returns:

    • (nil)
  • #reject!Enumerator

    Returns:



3214
3215
3216
3217
3218
3219
# File 'array.c', line 3214

static VALUE
rb_ary_reject_bang(VALUE ary)
{
    RETURN_SIZED_ENUMERATOR(ary, 0, 0, ary_enum_length);
    return ary_reject_bang(ary);
}

#repeated_combination(n) {|c| ... } ⇒ Object #repeated_combination(n) ⇒ Enumerator

When invoked with a block, yields all repeated combinations of length n of elements from the array and then returns the array itself.

The implementation makes no guarantees about the order in which the repeated combinations are yielded.

If no block is given, an Enumerator is returned instead.

Examples:

a = [1, 2, 3]
a.repeated_combination(1).to_a  #=> [[1], [2], [3]]
a.repeated_combination(2).to_a  #=> [[1,1],[1,2],[1,3],[2,2],[2,3],[3,3]]
a.repeated_combination(3).to_a  #=> [[1,1,1],[1,1,2],[1,1,3],[1,2,2],[1,2,3],
                                #    [1,3,3],[2,2,2],[2,2,3],[2,3,3],[3,3,3]]
a.repeated_combination(4).to_a  #=> [[1,1,1,1],[1,1,1,2],[1,1,1,3],[1,1,2,2],[1,1,2,3],
                                #    [1,1,3,3],[1,2,2,2],[1,2,2,3],[1,2,3,3],[1,3,3,3],
                                #    [2,2,2,2],[2,2,2,3],[2,2,3,3],[2,3,3,3],[3,3,3,3]]
a.repeated_combination(0).to_a  #=> [[]] # one combination of length 0

Overloads:



5250
5251
5252
5253
5254
5255
5256
5257
5258
5259
5260
5261
5262
5263
5264
5265
5266
5267
5268
5269
5270
5271
5272
5273
5274
5275
5276
5277
5278
5279
5280
5281
5282
5283
# File 'array.c', line 5250

static VALUE
rb_ary_repeated_combination(VALUE ary, VALUE num)
{
    long n, i, len;

    n = NUM2LONG(num);                 /* Combination size from argument */
    RETURN_SIZED_ENUMERATOR(ary, 1, &num, rb_ary_repeated_combination_size);   /* Return enumerator if no block */
    len = RARRAY_LEN(ary);
    if (n < 0) {
	/* yield nothing */
    }
    else if (n == 0) {
	rb_yield(rb_ary_new2(0));
    }
    else if (n == 1) {
	for (i = 0; i < len; i++) {
	    rb_yield(rb_ary_new3(1, RARRAY_AREF(ary, i)));
	}
    }
    else if (len == 0) {
	/* yield nothing */
    }
    else {
	volatile VALUE t0;
	long *p = ALLOCV_N(long, t0, n);
	VALUE ary0 = ary_make_shared_copy(ary); /* private defensive copy of ary */
	RBASIC_CLEAR_CLASS(ary0);

	rcombinate0(len, n, p, n, ary0); /* compute and yield repeated combinations */
	ALLOCV_END(t0);
	RBASIC_SET_CLASS_RAW(ary0, rb_cArray);
    }
    return ary;
}

#repeated_permutation(n) {|p| ... } ⇒ Object #repeated_permutation(n) ⇒ Enumerator

When invoked with a block, yield all repeated permutations of length n of the elements of the array, then return the array itself.

The implementation makes no guarantees about the order in which the repeated permutations are yielded.

If no block is given, an Enumerator is returned instead.

Examples:

a = [1, 2]
a.repeated_permutation(1).to_a  #=> [[1], [2]]
a.repeated_permutation(2).to_a  #=> [[1,1],[1,2],[2,1],[2,2]]
a.repeated_permutation(3).to_a  #=> [[1,1,1],[1,1,2],[1,2,1],[1,2,2],
                                #    [2,1,1],[2,1,2],[2,2,1],[2,2,2]]
a.repeated_permutation(0).to_a  #=> [[]] # one permutation of length 0

Overloads:



5156
5157
5158
5159
5160
5161
5162
5163
5164
5165
5166
5167
5168
5169
5170
5171
5172
5173
5174
5175
5176
5177
5178
5179
5180
5181
5182
5183
5184
5185
5186
5187
# File 'array.c', line 5156

static VALUE
rb_ary_repeated_permutation(VALUE ary, VALUE num)
{
    long r, n, i;

    n = RARRAY_LEN(ary);                  /* Array length */
    RETURN_SIZED_ENUMERATOR(ary, 1, &num, rb_ary_repeated_permutation_size);      /* Return Enumerator if no block */
    r = NUM2LONG(num);                    /* Permutation size from argument */

    if (r < 0) {
	/* no permutations: yield nothing */
    }
    else if (r == 0) { /* exactly one permutation: the zero-length array */
	rb_yield(rb_ary_new2(0));
    }
    else if (r == 1) { /* this is a special, easy case */
	for (i = 0; i < RARRAY_LEN(ary); i++) {
	    rb_yield(rb_ary_new3(1, RARRAY_AREF(ary, i)));
	}
    }
    else {             /* this is the general case */
	volatile VALUE t0;
	long *p = ALLOCV_N(long, t0, r);
	VALUE ary0 = ary_make_shared_copy(ary); /* private defensive copy of ary */
	RBASIC_CLEAR_CLASS(ary0);

	rpermute0(n, r, p, ary0); /* compute and yield repeated permutations */
	ALLOCV_END(t0);
	RBASIC_SET_CLASS_RAW(ary0, rb_cArray);
    }
    return ary;
}

#replace(other_ary) ⇒ Object #initialize_copy(other_ary) ⇒ Object

Replaces the contents of self with the contents of other_ary, truncating or expanding if necessary.

a = [ "a", "b", "c", "d", "e" ]
a.replace([ "x", "y", "z" ])   #=> ["x", "y", "z"]
a                              #=> ["x", "y", "z"]


3433
3434
3435
3436
3437
3438
3439
3440
3441
3442
3443
3444
3445
3446
3447
3448
3449
3450
3451
3452
3453
3454
3455
3456
3457
3458
3459
3460
3461
3462
3463
3464
3465
3466
3467
3468
3469
3470
3471
# File 'array.c', line 3433

VALUE
rb_ary_replace(VALUE copy, VALUE orig)
{
    rb_ary_modify_check(copy);
    orig = to_ary(orig);
    if (copy == orig) return copy;

    if (RARRAY_LEN(orig) <= RARRAY_EMBED_LEN_MAX) {
        VALUE shared = 0;

        if (ARY_OWNS_HEAP_P(copy)) {
	    RARRAY_PTR_USE(copy, ptr, ruby_sized_xfree(ptr, ARY_HEAP_SIZE(copy)));
	}
        else if (ARY_SHARED_P(copy)) {
            shared = ARY_SHARED(copy);
            FL_UNSET_SHARED(copy);
        }
        FL_SET_EMBED(copy);
	ary_memcpy(copy, 0, RARRAY_LEN(orig), RARRAY_CONST_PTR(orig));
        if (shared) {
            rb_ary_decrement_share(shared);
        }
        ARY_SET_LEN(copy, RARRAY_LEN(orig));
    }
    else {
        VALUE shared = ary_make_shared(orig);
        if (ARY_OWNS_HEAP_P(copy)) {
	    RARRAY_PTR_USE(copy, ptr, ruby_sized_xfree(ptr, ARY_HEAP_SIZE(copy)));
        }
        else {
            rb_ary_unshare_safe(copy);
        }
        FL_UNSET_EMBED(copy);
        ARY_SET_PTR(copy, RARRAY_CONST_PTR(orig));
        ARY_SET_LEN(copy, RARRAY_LEN(orig));
        rb_ary_set_shared(copy, shared);
    }
    return copy;
}

#reverseObject

Returns a new array containing self's elements in reverse order.

[ "a", "b", "c" ].reverse   #=> ["c", "b", "a"]
[ 1 ].reverse               #=> [1]


2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
# File 'array.c', line 2249

static VALUE
rb_ary_reverse_m(VALUE ary)
{
    long len = RARRAY_LEN(ary);
    VALUE dup = rb_ary_new2(len);

    if (len > 0) {
	const VALUE *p1 = RARRAY_CONST_PTR(ary);
	VALUE *p2 = (VALUE *)RARRAY_CONST_PTR(dup) + len - 1;
	do *p2-- = *p1++; while (--len > 0);
    }
    ARY_SET_LEN(dup, RARRAY_LEN(ary));
    return dup;
}

#reverse!Object

Reverses self in place.

a = [ "a", "b", "c" ]
a.reverse!       #=> ["c", "b", "a"]
a                #=> ["c", "b", "a"]


2233
2234
2235
2236
2237
# File 'array.c', line 2233

static VALUE
rb_ary_reverse_bang(VALUE ary)
{
    return rb_ary_reverse(ary);
}

#reverse_each {|item| ... } ⇒ Object #reverse_eachEnumerator

Same as Array#each, but traverses self in reverse order.

a = [ "a", "b", "c" ]
a.reverse_each {|x| print x, " " }

produces:

c b a

Overloads:



1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
# File 'array.c', line 1865

static VALUE
rb_ary_reverse_each(VALUE ary)
{
    long len;

    RETURN_SIZED_ENUMERATOR(ary, 0, 0, ary_enum_length);
    len = RARRAY_LEN(ary);
    while (len--) {
	long nlen;
	rb_yield(RARRAY_AREF(ary, len));
	nlen = RARRAY_LEN(ary);
	if (nlen < len) {
	    len = nlen;
	}
    }
    return ary;
}

#rindex(obj) ⇒ Integer? #rindex {|item| ... } ⇒ Integer? #rindexEnumerator

Returns the index of the last object in self == to obj.

If a block is given instead of an argument, returns the index of the first object for which the block returns true, starting from the last object.

Returns nil if no match is found.

See also Array#index.

If neither block nor argument is given, an Enumerator is returned instead.

a = [ "a", "b", "b", "b", "c" ]
a.rindex("b")             #=> 3
a.rindex("z")             #=> nil
a.rindex { |x| x == "b" } #=> 3

Overloads:



1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
# File 'array.c', line 1505

static VALUE
rb_ary_rindex(int argc, VALUE *argv, VALUE ary)
{
    const VALUE *ptr;
    VALUE val;
    long i = RARRAY_LEN(ary), len;

    if (argc == 0) {
	RETURN_ENUMERATOR(ary, 0, 0);
	while (i--) {
	    if (RTEST(rb_yield(RARRAY_AREF(ary, i))))
		return LONG2NUM(i);
	    if (i > (len = RARRAY_LEN(ary))) {
		i = len;
	    }
	}
	return Qnil;
    }
    rb_check_arity(argc, 0, 1);
    val = argv[0];
    if (rb_block_given_p())
	rb_warn("given block not used");
    ptr = RARRAY_CONST_PTR(ary);
    while (i--) {
	VALUE e = ptr[i];
	switch (rb_equal_opt(e, val)) {
	  case Qundef:
	    if (!rb_equal(e, val)) break;
	  case Qtrue:
	    return LONG2NUM(i);
	  case Qfalse:
	    continue;
	}
	if (i > (len = RARRAY_LEN(ary))) {
	    i = len;
	}
	ptr = RARRAY_CONST_PTR(ary);
    }
    return Qnil;
}

#rotate(count = 1) ⇒ Object

Returns a new array by rotating self so that the element at count is the first element of the new array.

If count is negative then it rotates in the opposite direction, starting from the end of self where -1 is the last element.

a = [ "a", "b", "c", "d" ]
a.rotate         #=> ["b", "c", "d", "a"]
a                #=> ["a", "b", "c", "d"]
a.rotate(2)      #=> ["c", "d", "a", "b"]
a.rotate(-3)     #=> ["b", "c", "d", "a"]


2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
# File 'array.c', line 2339

static VALUE
rb_ary_rotate_m(int argc, VALUE *argv, VALUE ary)
{
    VALUE rotated;
    const VALUE *ptr;
    long len, cnt = 1;

    switch (argc) {
      case 1: cnt = NUM2LONG(argv[0]);
      case 0: break;
      default: rb_scan_args(argc, argv, "01", NULL);
    }

    len = RARRAY_LEN(ary);
    rotated = rb_ary_new2(len);
    if (len > 0) {
	cnt = rotate_count(cnt, len);
	ptr = RARRAY_CONST_PTR(ary);
	len -= cnt;
	ary_memcpy(rotated, 0, len, ptr + cnt);
	ary_memcpy(rotated, len, cnt, ptr);
    }
    ARY_SET_LEN(rotated, RARRAY_LEN(ary));
    return rotated;
}

#rotate!(count = 1) ⇒ Object

Rotates self in place so that the element at count comes first, and returns self.

If count is negative then it rotates in the opposite direction, starting from the end of the array where -1 is the last element.

a = [ "a", "b", "c", "d" ]
a.rotate!        #=> ["b", "c", "d", "a"]
a                #=> ["b", "c", "d", "a"]
a.rotate!(2)     #=> ["d", "a", "b", "c"]
a.rotate!(-3)    #=> ["a", "b", "c", "d"]


2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
# File 'array.c', line 2308

static VALUE
rb_ary_rotate_bang(int argc, VALUE *argv, VALUE ary)
{
    long n = 1;

    switch (argc) {
      case 1: n = NUM2LONG(argv[0]);
      case 0: break;
      default: rb_scan_args(argc, argv, "01", NULL);
    }
    rb_ary_rotate(ary, n);
    return ary;
}

#sampleObject #sample(random: rng) ⇒ Object #sample(n) ⇒ Object #sample(n, random: rng) ⇒ Object

Choose a random element or n random elements from the array.

The elements are chosen by using random and unique indices into the array in order to ensure that an element doesn't repeat itself unless the array already contained duplicate elements.

If the array is empty the first form returns nil and the second form returns an empty array.

The optional rng argument will be used as the random number generator.

a = [ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 ]
a.sample         #=> 7
a.sample(4)      #=> [6, 4, 2, 5]

Overloads:



4655
4656
4657
4658
4659
4660
4661
4662
4663
4664
4665
4666
4667
4668
4669
4670
4671
4672
4673
4674
4675
4676
4677
4678
4679
4680
4681
4682
4683
4684
4685
4686
4687
4688
4689
4690
4691
4692
4693
4694
4695
4696
4697
4698
4699
4700
4701
4702
4703
4704
4705
4706
4707
4708
4709
4710
4711
4712
4713
4714
4715
4716
4717
4718
4719
4720
4721
4722
4723
4724
4725
4726
4727
4728
4729
4730
4731
4732
4733
4734
4735
4736
4737
4738
4739
4740
4741
4742
4743
4744
4745
4746
4747
4748
4749
4750
4751
4752
4753
4754
4755
4756
4757
# File 'array.c', line 4655

static VALUE
rb_ary_sample(int argc, VALUE *argv, VALUE ary)
{
    VALUE nv, result;
    VALUE opts, randgen = rb_cRandom;
    long n, len, i, j, k, idx[10];
    long rnds[numberof(idx)];

    if (OPTHASH_GIVEN_P(opts)) {
	VALUE rnd;
	ID keyword_ids[1];

	keyword_ids[0] = id_random;
	rb_get_kwargs(opts, keyword_ids, 0, 1, &rnd);
	if (rnd != Qundef) {
	    randgen = rnd;
	}
    }
    len = RARRAY_LEN(ary);
    if (argc == 0) {
	if (len < 2)
	    i = 0;
	else
	    i = RAND_UPTO(len);

	return rb_ary_elt(ary, i);
    }
    rb_scan_args(argc, argv, "1", &nv);
    n = NUM2LONG(nv);
    if (n < 0) rb_raise(rb_eArgError, "negative sample number");
    if (n > len) n = len;
    if (n <= numberof(idx)) {
	for (i = 0; i < n; ++i) {
	    rnds[i] = RAND_UPTO(len - i);
	}
    }
    k = len;
    len = RARRAY_LEN(ary);
    if (len < k && n <= numberof(idx)) {
	for (i = 0; i < n; ++i) {
	    if (rnds[i] >= len) return rb_ary_new_capa(0);
	}
    }
    if (n > len) n = len;
    switch (n) {
      case 0:
	return rb_ary_new_capa(0);
      case 1:
	i = rnds[0];
	return rb_ary_new_from_values(1, &RARRAY_AREF(ary, i));
      case 2:
	i = rnds[0];
	j = rnds[1];
	if (j >= i) j++;
	return rb_ary_new_from_args(2, RARRAY_AREF(ary, i), RARRAY_AREF(ary, j));
      case 3:
	i = rnds[0];
	j = rnds[1];
	k = rnds[2];
	{
	    long l = j, g = i;
	    if (j >= i) l = i, g = ++j;
	    if (k >= l && (++k >= g)) ++k;
	}
	return rb_ary_new_from_args(3, RARRAY_AREF(ary, i), RARRAY_AREF(ary, j), RARRAY_AREF(ary, k));
    }
    if (n <= numberof(idx)) {
	long sorted[numberof(idx)];
	sorted[0] = idx[0] = rnds[0];
	for (i=1; i<n; i++) {
	    k = rnds[i];
	    for (j = 0; j < i; ++j) {
		if (k < sorted[j]) break;
		++k;
	    }
	    memmove(&sorted[j+1], &sorted[j], sizeof(sorted[0])*(i-j));
	    sorted[j] = idx[i] = k;
	}
	result = rb_ary_new_capa(n);
	RARRAY_PTR_USE(result, ptr_result, {
	    for (i=0; i<n; i++) {
		ptr_result[i] = RARRAY_AREF(ary, idx[i]);
	    }
	});
    }
    else {
	result = rb_ary_dup(ary);
	RBASIC_CLEAR_CLASS(result);
	RB_GC_GUARD(ary);
	RARRAY_PTR_USE(result, ptr_result, {
	    for (i=0; i<n; i++) {
		j = RAND_UPTO(len-i) + i;
		nv = ptr_result[j];
		ptr_result[j] = ptr_result[i];
		ptr_result[i] = nv;
	    }
	});
	RBASIC_SET_CLASS_RAW(result, rb_cArray);
    }
    ARY_SET_LEN(result, n);

    return result;
}

#select {|item| ... } ⇒ Object #selectEnumerator

Returns a new array containing all elements of ary for which the given block returns a true value.

If no block is given, an Enumerator is returned instead.

[1,2,3,4,5].select { |num|  num.even?  }   #=> [2, 4]

a = %w{ a b c d e f }
a.select { |v| v =~ /[aeiou]/ }  #=> ["a", "e"]

See also Enumerable#select.

Overloads:



2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
# File 'array.c', line 2842

static VALUE
rb_ary_select(VALUE ary)
{
    VALUE result;
    long i;

    RETURN_SIZED_ENUMERATOR(ary, 0, 0, ary_enum_length);
    result = rb_ary_new2(RARRAY_LEN(ary));
    for (i = 0; i < RARRAY_LEN(ary); i++) {
	if (RTEST(rb_yield(RARRAY_AREF(ary, i)))) {
	    rb_ary_push(result, rb_ary_elt(ary, i));
	}
    }
    return result;
}

#select! {|item| ... } ⇒ nil #select!Enumerator

Invokes the given block passing in successive elements from self, deleting elements for which the block returns a false value.

The array may not be changed instantly every time the block is called.

If changes were made, it will return self, otherwise it returns nil.

See also Array#keep_if

If no block is given, an Enumerator is returned instead.

Overloads:

  • #select! {|item| ... } ⇒ nil

    Yields:

    • (item)

    Returns:

    • (nil)
  • #select!Enumerator

    Returns:



2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
# File 'array.c', line 2918

static VALUE
rb_ary_select_bang(VALUE ary)
{
    struct select_bang_arg args;

    RETURN_SIZED_ENUMERATOR(ary, 0, 0, ary_enum_length);
    rb_ary_modify(ary);

    args.ary = ary;
    args.len[0] = args.len[1] = 0;
    return rb_ensure(select_bang_i, (VALUE)&args, select_bang_ensure, (VALUE)&args);
}

#shiftObject? #shift(n) ⇒ Object

Removes the first element of self and returns it (shifting all other elements down by one). Returns nil if the array is empty.

If a number n is given, returns an array of the first n elements (or less) just like array.slice!(0, n) does. With ary containing only the remainder elements, not including what was shifted to new_ary. See also Array#unshift for the opposite effect.

args = [ "-m", "-q", "filename" ]
args.shift     #=> "-m"
args           #=> ["-q", "filename"]

args = [ "-m", "-q", "filename" ]
args.shift(2)  #=> ["-m", "-q"]
args           #=> ["filename"]

Overloads:



1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
# File 'array.c', line 1053

static VALUE
rb_ary_shift_m(int argc, VALUE *argv, VALUE ary)
{
    VALUE result;
    long n;

    if (argc == 0) {
	return rb_ary_shift(ary);
    }

    rb_ary_modify_check(ary);
    result = ary_take_first_or_last(argc, argv, ary, ARY_TAKE_FIRST);
    n = RARRAY_LEN(result);
    if (ARY_SHARED_P(ary)) {
	if (ARY_SHARED_OCCUPIED(ARY_SHARED(ary))) {
	  setup_occupied_shared:
	    ary_mem_clear(ary, 0, n);
	}
        ARY_INCREASE_PTR(ary, n);
    }
    else {
	if (RARRAY_LEN(ary) < ARY_DEFAULT_SIZE) {
	    RARRAY_PTR_USE(ary, ptr, {
		MEMMOVE(ptr, ptr+n, VALUE, RARRAY_LEN(ary)-n);
	    }); /* WB: no new reference */
	}
	else {
	    ary_make_shared(ary);
	    goto setup_occupied_shared;
	}
    }
    ARY_INCREASE_LEN(ary, -n);

    return result;
}

#shuffleObject #shuffle(random: rng) ⇒ Object

Returns a new array with elements of self shuffled.

a = [ 1, 2, 3 ]           #=> [1, 2, 3]
a.shuffle                 #=> [2, 3, 1]
a                         #=> [1, 2, 3]

The optional rng argument will be used as the random number generator.

a.shuffle(random: Random.new(1))  #=> [1, 3, 2]


4622
4623
4624
4625
4626
4627
4628
# File 'array.c', line 4622

static VALUE
rb_ary_shuffle(int argc, VALUE *argv, VALUE ary)
{
    ary = rb_ary_dup(ary);
    rb_ary_shuffle_bang(argc, argv, ary);
    return ary;
}

#shuffle!Object #shuffle!(random: rng) ⇒ Object

Shuffles elements in self in place.

a = [ 1, 2, 3 ]           #=> [1, 2, 3]
a.shuffle!                #=> [2, 3, 1]
a                         #=> [2, 3, 1]

The optional rng argument will be used as the random number generator.

a.shuffle!(random: Random.new(1))  #=> [1, 3, 2]


4571
4572
4573
4574
4575
4576
4577
4578
4579
4580
4581
4582
4583
4584
4585
4586
4587
4588
4589
4590
4591
4592
4593
4594
4595
4596
4597
4598
4599
4600
4601
4602
4603
# File 'array.c', line 4571

static VALUE
rb_ary_shuffle_bang(int argc, VALUE *argv, VALUE ary)
{
    VALUE opts, randgen = rb_cRandom;
    long i, len;

    if (OPTHASH_GIVEN_P(opts)) {
	VALUE rnd;
	ID keyword_ids[1];

	keyword_ids[0] = id_random;
	rb_get_kwargs(opts, keyword_ids, 0, 1, &rnd);
	if (rnd != Qundef) {
	    randgen = rnd;
	}
    }
    rb_check_arity(argc, 0, 0);
    rb_ary_modify(ary);
    i = len = RARRAY_LEN(ary);
    RARRAY_PTR_USE(ary, ptr, {
	while (i) {
	    long j = RAND_UPTO(i);
	    VALUE tmp;
	    if (len != RARRAY_LEN(ary) || ptr != RARRAY_CONST_PTR(ary)) {
		rb_raise(rb_eRuntimeError, "modified during shuffle");
	    }
	    tmp = ptr[--i];
	    ptr[i] = ptr[j];
	    ptr[j] = tmp;
	}
    }); /* WB: no new reference */
    return ary;
}

#[](index) ⇒ Object? #[](start, length) ⇒ nil #[](range) ⇒ nil #slice(index) ⇒ Object? #slice(start, length) ⇒ nil #slice(range) ⇒ nil

Element Reference — Returns the element at index, or returns a subarray starting at the start index and continuing for length elements, or returns a subarray specified by range of indices.

Negative indices count backward from the end of the array (-1 is the last element). For start and range cases the starting index is just before an element. Additionally, an empty array is returned when the starting index for an element range is at the end of the array.

Returns nil if the index (or starting index) are out of range.

a = [ "a", "b", "c", "d", "e" ]
a[2] +  a[0] + a[1]    #=> "cab"
a[6]                   #=> nil
a[1, 2]                #=> [ "b", "c" ]
a[1..3]                #=> [ "b", "c", "d" ]
a[4..7]                #=> [ "e" ]
a[6..10]               #=> nil
a[-3, 3]               #=> [ "c", "d", "e" ]
# special cases
a[5]                   #=> nil
a[6, 1]                #=> nil
a[5, 1]                #=> []
a[5..10]               #=> []

Overloads:

  • #[](index) ⇒ Object?

    Returns:

  • #[](start, length) ⇒ nil

    Returns:

    • (nil)
  • #[](range) ⇒ nil

    Returns:

    • (nil)
  • #slice(index) ⇒ Object?

    Returns:

  • #slice(start, length) ⇒ nil

    Returns:

    • (nil)
  • #slice(range) ⇒ nil

    Returns:

    • (nil)


1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
# File 'array.c', line 1258

VALUE
rb_ary_aref(int argc, const VALUE *argv, VALUE ary)
{
    VALUE arg;
    long beg, len;

    if (argc == 2) {
	beg = NUM2LONG(argv[0]);
	len = NUM2LONG(argv[1]);
	if (beg < 0) {
	    beg += RARRAY_LEN(ary);
	}
	return rb_ary_subseq(ary, beg, len);
    }
    if (argc != 1) {
	rb_scan_args(argc, argv, "11", NULL, NULL);
    }
    arg = argv[0];
    /* special case - speeding up */
    if (FIXNUM_P(arg)) {
	return rb_ary_entry(ary, FIX2LONG(arg));
    }
    /* check if idx is Range */
    switch (rb_range_beg_len(arg, &beg, &len, RARRAY_LEN(ary), 0)) {
      case Qfalse:
	break;
      case Qnil:
	return Qnil;
      default:
	return rb_ary_subseq(ary, beg, len);
    }
    return rb_ary_entry(ary, NUM2LONG(arg));
}

#slice!(index) ⇒ Object? #slice!(start, length) ⇒ nil #slice!(range) ⇒ nil

Deletes the element(s) given by an index (optionally up to length elements) or by a range.

Returns the deleted object (or objects), or nil if the index is out of range.

a = [ "a", "b", "c" ]
a.slice!(1)     #=> "b"
a               #=> ["a", "c"]
a.slice!(-1)    #=> "c"
a               #=> ["a"]
a.slice!(100)   #=> nil
a               #=> ["a"]

Overloads:

  • #slice!(index) ⇒ Object?

    Returns:

  • #slice!(start, length) ⇒ nil

    Returns:

    • (nil)
  • #slice!(range) ⇒ nil

    Returns:

    • (nil)


3105
3106
3107
3108
3109
3110
3111
3112
3113
3114
3115
3116
3117
3118
3119
3120
3121
3122
3123
3124
3125
3126
3127
3128
3129
3130
3131
3132
3133
3134
3135
3136
3137
3138
3139
3140
3141
3142
3143
3144
3145
3146
3147
3148
3149
3150
3151
3152
3153
3154
# File 'array.c', line 3105

static VALUE
rb_ary_slice_bang(int argc, VALUE *argv, VALUE ary)
{
    VALUE arg1, arg2;
    long pos, len, orig_len;

    rb_ary_modify_check(ary);
    if (argc == 2) {
	pos = NUM2LONG(argv[0]);
	len = NUM2LONG(argv[1]);
      delete_pos_len:
	if (len < 0) return Qnil;
	orig_len = RARRAY_LEN(ary);
	if (pos < 0) {
	    pos += orig_len;
	    if (pos < 0) return Qnil;
	}
	else if (orig_len < pos) return Qnil;
	if (orig_len < pos + len) {
	    len = orig_len - pos;
	}
	if (len == 0) return rb_ary_new2(0);
	arg2 = rb_ary_new4(len, RARRAY_CONST_PTR(ary)+pos);
	RBASIC_SET_CLASS(arg2, rb_obj_class(ary));
	rb_ary_splice(ary, pos, len, Qundef);
	return arg2;
    }

    if (argc != 1) {
	/* error report */
	rb_scan_args(argc, argv, "11", NULL, NULL);
    }
    arg1 = argv[0];

    if (!FIXNUM_P(arg1)) {
	switch (rb_range_beg_len(arg1, &pos, &len, RARRAY_LEN(ary), 0)) {
	  case Qtrue:
	    /* valid range */
	    goto delete_pos_len;
	  case Qnil:
	    /* invalid range */
	    return Qnil;
	  default:
	    /* not a range */
	    break;
	}
    }

    return rb_ary_delete_at(ary, NUM2LONG(arg1));
}

#sortObject #sort {|a, b| ... } ⇒ Object

Returns a new array created by sorting self.

Comparisons for the sort will be done using the <=> operator or using an optional code block.

The block must implement a comparison between a and b and return an integer less than 0 when b follows a, 0 when a and b are equivalent, or an integer greater than 0 when a follows b.

See also Enumerable#sort_by.

a = [ "d", "a", "e", "c", "b" ]
a.sort                    #=> ["a", "b", "c", "d", "e"]
a.sort { |x,y| y <=> x }  #=> ["e", "d", "c", "b", "a"]

Overloads:

  • #sort {|a, b| ... } ⇒ Object

    Yields:

    • (a, b)


2537
2538
2539
2540
2541
2542
2543
# File 'array.c', line 2537

VALUE
rb_ary_sort(VALUE ary)
{
    ary = rb_ary_dup(ary);
    rb_ary_sort_bang(ary);
    return ary;
}

#sort!Object #sort! {|a, b| ... } ⇒ Object

Sorts self in place.

Comparisons for the sort will be done using the <=> operator or using an optional code block.

The block must implement a comparison between a and b and return an integer less than 0 when b follows a, 0 when a and b are equivalent, or an integer greater than 0 when a follows b.

See also Enumerable#sort_by.

a = [ "d", "a", "e", "c", "b" ]
a.sort!                    #=> ["a", "b", "c", "d", "e"]
a.sort! { |x,y| y <=> x }  #=> ["e", "d", "c", "b", "a"]

Overloads:

  • #sort! {|a, b| ... } ⇒ Object

    Yields:

    • (a, b)


2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
# File 'array.c', line 2455

VALUE
rb_ary_sort_bang(VALUE ary)
{
    rb_ary_modify(ary);
    assert(!ARY_SHARED_P(ary));
    if (RARRAY_LEN(ary) > 1) {
	VALUE tmp = ary_make_substitution(ary); /* only ary refers tmp */
	struct ary_sort_data data;
	long len = RARRAY_LEN(ary);

	RBASIC_CLEAR_CLASS(tmp);
	data.ary = tmp;
	data.opt_methods = 0;
	data.opt_inited = 0;
	RARRAY_PTR_USE(tmp, ptr, {
	    ruby_qsort(ptr, len, sizeof(VALUE),
		       rb_block_given_p()?sort_1:sort_2, &data);
	}); /* WB: no new reference */
	rb_ary_modify(ary);
        if (ARY_EMBED_P(tmp)) {
            if (ARY_SHARED_P(ary)) { /* ary might be destructively operated in the given block */
                rb_ary_unshare(ary);
		FL_SET_EMBED(ary);
            }
	    ary_memcpy(ary, 0, ARY_EMBED_LEN(tmp), ARY_EMBED_PTR(tmp));
            ARY_SET_LEN(ary, ARY_EMBED_LEN(tmp));
        }
        else {
            if (!ARY_EMBED_P(ary) && ARY_HEAP_PTR(ary) == ARY_HEAP_PTR(tmp)) {
                FL_UNSET_SHARED(ary);
                ARY_SET_CAPA(ary, RARRAY_LEN(tmp));
            }
            else {
                assert(!ARY_SHARED_P(tmp));
                if (ARY_EMBED_P(ary)) {
                    FL_UNSET_EMBED(ary);
                }
                else if (ARY_SHARED_P(ary)) {
                    /* ary might be destructively operated in the given block */
                    rb_ary_unshare(ary);
                }
                else {
		    ruby_sized_xfree((void *)ARY_HEAP_PTR(ary), ARY_HEAP_SIZE(ary));
                }
                ARY_SET_PTR(ary, RARRAY_CONST_PTR(tmp));
                ARY_SET_HEAP_LEN(ary, len);
                ARY_SET_CAPA(ary, RARRAY_LEN(tmp));
            }
            /* tmp was lost ownership for the ptr */
            FL_UNSET(tmp, FL_FREEZE);
            FL_SET_EMBED(tmp);
            ARY_SET_EMBED_LEN(tmp, 0);
            FL_SET(tmp, FL_FREEZE);
	}
        /* tmp will be GC'ed. */
        RBASIC_SET_CLASS_RAW(tmp, rb_cArray); /* rb_cArray must be marked */
    }
    return ary;
}

#sort_by! {|obj| ... } ⇒ Object #sort_by!Enumerator

Sorts self in place using a set of keys generated by mapping the values in self through the given block.

If no block is given, an Enumerator is returned instead.

Overloads:



2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
# File 'array.c', line 2690

static VALUE
rb_ary_sort_by_bang(VALUE ary)
{
    VALUE sorted;

    RETURN_SIZED_ENUMERATOR(ary, 0, 0, ary_enum_length);
    rb_ary_modify(ary);
    sorted = rb_block_call(ary, rb_intern("sort_by"), 0, 0, sort_by_i, 0);
    rb_ary_replace(ary, sorted);
    return ary;
}

#take(n) ⇒ Object

Returns first n elements from the array.

If a negative number is given, raises an ArgumentError.

See also Array#drop

a = [1, 2, 3, 4, 5, 0]
a.take(3)             #=> [1, 2, 3]


5410
5411
5412
5413
5414
5415
5416
5417
5418
# File 'array.c', line 5410

static VALUE
rb_ary_take(VALUE obj, VALUE n)
{
    long len = NUM2LONG(n);
    if (len < 0) {
	rb_raise(rb_eArgError, "attempt to take negative size");
    }
    return rb_ary_subseq(obj, 0, len);
}

#take_while {|obj| ... } ⇒ Object #take_whileEnumerator

Passes elements to the block until the block returns nil or false, then stops iterating and returns an array of all prior elements.

If no block is given, an Enumerator is returned instead.

See also Array#drop_while

a = [1, 2, 3, 4, 5, 0]
a.take_while { |i| i < 3 }  #=> [1, 2]

Overloads:



5437
5438
5439
5440
5441
5442
5443
5444
5445
5446
5447
# File 'array.c', line 5437

static VALUE
rb_ary_take_while(VALUE ary)
{
    long i;

    RETURN_ENUMERATOR(ary, 0, 0);
    for (i = 0; i < RARRAY_LEN(ary); i++) {
	if (!RTEST(rb_yield(RARRAY_AREF(ary, i)))) break;
    }
    return rb_ary_take(ary, LONG2FIX(i));
}

#to_aObject

Returns self.

If called on a subclass of Array, converts the receiver to an Array object.



2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
# File 'array.c', line 2140

static VALUE
rb_ary_to_a(VALUE ary)
{
    if (rb_obj_class(ary) != rb_cArray) {
	VALUE dup = rb_ary_new2(RARRAY_LEN(ary));
	rb_ary_replace(dup, ary);
	return dup;
    }
    return ary;
}

#to_aryObject

Returns self.



2190
2191
2192
2193
2194
# File 'array.c', line 2190

static VALUE
rb_ary_to_ary_m(VALUE ary)
{
    return ary;
}

#to_hHash

Returns the result of interpreting ary as an array of [key, value] pairs.

[[:foo, :bar], [1, 2]].to_h
  # => {:foo => :bar, 1 => 2}

Returns:



2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
# File 'array.c', line 2162

static VALUE
rb_ary_to_h(VALUE ary)
{
    long i;
    VALUE hash = rb_hash_new();
    for (i=0; i<RARRAY_LEN(ary); i++) {
	const VALUE elt = rb_ary_elt(ary, i);
	const VALUE key_value_pair = rb_check_array_type(elt);
	if (NIL_P(key_value_pair)) {
	    rb_raise(rb_eTypeError, "wrong element type %"PRIsVALUE" at %ld (expected array)",
		     rb_obj_class(elt), i);
	}
	if (RARRAY_LEN(key_value_pair) != 2) {
	    rb_raise(rb_eArgError, "wrong array length at %ld (expected 2, was %ld)",
		i, RARRAY_LEN(key_value_pair));
	}
	rb_hash_aset(hash, RARRAY_AREF(key_value_pair, 0), RARRAY_AREF(key_value_pair, 1));
    }
    return hash;
}

#transposeObject

Assumes that self is an array of arrays and transposes the rows and columns.

a = [[1,2], [3,4], [5,6]]
a.transpose   #=> [[1, 3, 5], [2, 4, 6]]

If the length of the subarrays don't match, an IndexError is raised.



3392
3393
3394
3395
3396
3397
3398
3399
3400
3401
3402
3403
3404
3405
3406
3407
3408
3409
3410
3411
3412
3413
3414
3415
3416
3417
3418
# File 'array.c', line 3392

static VALUE
rb_ary_transpose(VALUE ary)
{
    long elen = -1, alen, i, j;
    VALUE tmp, result = 0;

    alen = RARRAY_LEN(ary);
    if (alen == 0) return rb_ary_dup(ary);
    for (i=0; i<alen; i++) {
	tmp = to_ary(rb_ary_elt(ary, i));
	if (elen < 0) {		/* first element */
	    elen = RARRAY_LEN(tmp);
	    result = rb_ary_new2(elen);
	    for (j=0; j<elen; j++) {
		rb_ary_store(result, j, rb_ary_new2(alen));
	    }
	}
	else if (elen != RARRAY_LEN(tmp)) {
	    rb_raise(rb_eIndexError, "element size differs (%ld should be %ld)",
		     RARRAY_LEN(tmp), elen);
	}
	for (j=0; j<elen; j++) {
	    rb_ary_store(rb_ary_elt(result, j), i, rb_ary_elt(tmp, j));
	}
    }
    return result;
}

#uniqObject #uniq {|item| ... } ⇒ Object

Returns a new array by removing duplicate values in self.

If a block is given, it will use the return value of the block for comparison.

It compares values using their #hash and #eql? methods for efficiency.

self is traversed in order, and the first occurrence is kept.

a = [ "a", "a", "b", "b", "c" ]
a.uniq   # => ["a", "b", "c"]

b = [["student","sam"], ["student","george"], ["teacher","matz"]]
b.uniq { |s| s.first } # => [["student", "sam"], ["teacher", "matz"]]

Overloads:

  • #uniq {|item| ... } ⇒ Object

    Yields:

    • (item)


4284
4285
4286
4287
4288
4289
4290
4291
4292
4293
4294
4295
4296
4297
4298
4299
4300
4301
4302
4303
# File 'array.c', line 4284

static VALUE
rb_ary_uniq(VALUE ary)
{
    VALUE hash, uniq;

    if (RARRAY_LEN(ary) <= 1)
        return rb_ary_dup(ary);
    if (rb_block_given_p()) {
	hash = ary_make_hash_by(ary);
	uniq = rb_hash_values(hash);
    }
    else {
	hash = ary_make_hash(ary);
	uniq = rb_hash_values(hash);
    }
    RBASIC_SET_CLASS(uniq, rb_obj_class(ary));
    ary_recycle_hash(hash);

    return uniq;
}

#uniq!nil #uniq! {|item| ... } ⇒ nil

Removes duplicate elements from self.

If a block is given, it will use the return value of the block for comparison.

It compares values using their #hash and #eql? methods for efficiency.

self is traversed in order, and the first occurrence is kept.

Returns nil if no changes are made (that is, no duplicates are found).

a = [ "a", "a", "b", "b", "c" ]
a.uniq!   # => ["a", "b", "c"]

b = [ "a", "b", "c" ]
b.uniq!   # => nil

c = [["student","sam"], ["student","george"], ["teacher","matz"]]
c.uniq! { |s| s.first } # => [["student", "sam"], ["teacher", "matz"]]

Overloads:

  • #uniq!nil

    Returns:

    • (nil)
  • #uniq! {|item| ... } ⇒ nil

    Yields:

    • (item)

    Returns:

    • (nil)


4232
4233
4234
4235
4236
4237
4238
4239
4240
4241
4242
4243
4244
4245
4246
4247
4248
4249
4250
4251
4252
4253
4254
4255
4256
4257
4258
4259
4260
4261
# File 'array.c', line 4232

static VALUE
rb_ary_uniq_bang(VALUE ary)
{
    VALUE hash;
    long hash_size;

    rb_ary_modify_check(ary);
    if (RARRAY_LEN(ary) <= 1)
        return Qnil;
    if (rb_block_given_p())
	hash = ary_make_hash_by(ary);
    else
	hash = ary_make_hash(ary);

    hash_size = RHASH_SIZE(hash);
    if (RARRAY_LEN(ary) == hash_size) {
	return Qnil;
    }
    rb_ary_modify_check(ary);
    ARY_SET_LEN(ary, 0);
    if (ARY_SHARED_P(ary) && !ARY_EMBED_P(ary)) {
	rb_ary_unshare(ary);
	FL_SET_EMBED(ary);
    }
    ary_resize_capa(ary, hash_size);
    st_foreach(rb_hash_tbl_raw(hash), push_value, ary);
    ary_recycle_hash(hash);

    return ary;
}

#unshift(obj, ...) ⇒ Object

Prepends objects to the front of self, moving other elements upwards. See also Array#shift for the opposite effect.

a = [ "b", "c", "d" ]
a.unshift("a")   #=> ["a", "b", "c", "d"]
a.unshift(1, 2)  #=> [ 1, 2, "a", "b", "c", "d"]


1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
# File 'array.c', line 1160

static VALUE
rb_ary_unshift_m(int argc, VALUE *argv, VALUE ary)
{
    long len = RARRAY_LEN(ary);
    VALUE target_ary;

    if (argc == 0) {
	rb_ary_modify_check(ary);
	return ary;
    }

    target_ary = ary_ensure_room_for_unshift(ary, argc);
    ary_memcpy0(ary, 0, argc, argv, target_ary);
    ARY_SET_LEN(ary, len + argc);
    return ary;
}

#values_at(selector, ...) ⇒ Object

Returns an array containing the elements in self corresponding to the given selector(s).

The selectors may be either integer indices or ranges.

See also Array#select.

a = %w{ a b c d e f }
a.values_at(1, 3, 5)          # => ["b", "d", "f"]
a.values_at(1, 3, 5, 7)       # => ["b", "d", "f", nil]
a.values_at(-1, -2, -2, -7)   # => ["f", "e", "e", nil]
a.values_at(4..6, 3...6)      # => ["e", "f", nil, "d", "e", "f"]


2817
2818
2819
2820
2821
# File 'array.c', line 2817

static VALUE
rb_ary_values_at(int argc, VALUE *argv, VALUE ary)
{
    return rb_get_values_at(ary, RARRAY_LEN(ary), argc, argv, rb_ary_entry);
}

#zip(arg, ...) ⇒ Object #zip(arg, ...) {|arr| ... } ⇒ nil

Converts any arguments to arrays, then merges elements of self with corresponding elements from each argument.

This generates a sequence of ary.size n-element arrays, where n is one more than the count of arguments.

If the size of any argument is less than the size of the initial array, nil values are supplied.

If a block is given, it is invoked for each output array, otherwise an array of arrays is returned.

a = [ 4, 5, 6 ]
b = [ 7, 8, 9 ]
[1, 2, 3].zip(a, b)   #=> [[1, 4, 7], [2, 5, 8], [3, 6, 9]]
[1, 2].zip(a, b)      #=> [[1, 4, 7], [2, 5, 8]]
a.zip([1, 2], [8])    #=> [[4, 1, 8], [5, 2, nil], [6, nil, nil]]

Overloads:

  • #zip(arg, ...) {|arr| ... } ⇒ nil

    Yields:

    • (arr)

    Returns:

    • (nil)


3321
3322
3323
3324
3325
3326
3327
3328
3329
3330
3331
3332
3333
3334
3335
3336
3337
3338
3339
3340
3341
3342
3343
3344
3345
3346
3347
3348
3349
3350
3351
3352
3353
3354
3355
3356
3357
3358
3359
3360
3361
3362
3363
3364
3365
3366
3367
3368
3369
3370
3371
3372
3373
3374
3375
3376
3377
# File 'array.c', line 3321

static VALUE
rb_ary_zip(int argc, VALUE *argv, VALUE ary)
{
    int i, j;
    long len = RARRAY_LEN(ary);
    VALUE result = Qnil;

    for (i=0; i<argc; i++) {
	argv[i] = take_items(argv[i], len);
    }

    if (rb_block_given_p()) {
	int arity = rb_block_arity();

	if (arity > 1) {
	    VALUE work, *tmp;

	    tmp = ALLOCV_N(VALUE, work, argc+1);

	    for (i=0; i<RARRAY_LEN(ary); i++) {
		tmp[0] = RARRAY_AREF(ary, i);
		for (j=0; j<argc; j++) {
		    tmp[j+1] = rb_ary_elt(argv[j], i);
		}
		rb_yield_values2(argc+1, tmp);
	    }

	    if (work) ALLOCV_END(work);
	}
	else {
	    for (i=0; i<RARRAY_LEN(ary); i++) {
		VALUE tmp = rb_ary_new2(argc+1);

		rb_ary_push(tmp, RARRAY_AREF(ary, i));
		for (j=0; j<argc; j++) {
		    rb_ary_push(tmp, rb_ary_elt(argv[j], i));
		}
		rb_yield(tmp);
	    }
	}
    }
    else {
	result = rb_ary_new_capa(len);

	for (i=0; i<len; i++) {
	    VALUE tmp = rb_ary_new_capa(argc+1);

	    rb_ary_push(tmp, RARRAY_AREF(ary, i));
	    for (j=0; j<argc; j++) {
		rb_ary_push(tmp, rb_ary_elt(argv[j], i));
	    }
	    rb_ary_push(result, tmp);
	}
    }

    return result;
}

#|(other_ary) ⇒ Object

Set Union — Returns a new array by joining ary with other_ary, excluding any duplicates and preserving the order from the original array.

It compares elements using their #hash and #eql? methods for efficiency.

[ "a", "b", "c" ] | [ "c", "d", "a" ]    #=> [ "a", "b", "c", "d" ]

See also Array#uniq.



4178
4179
4180
4181
4182
4183
4184
4185
4186
4187
4188
4189
4190
4191
4192
4193
4194
4195
4196
# File 'array.c', line 4178

static VALUE
rb_ary_or(VALUE ary1, VALUE ary2)
{
    VALUE hash, ary3;
    long i;

    ary2 = to_ary(ary2);
    hash = ary_make_hash(ary1);

    for (i=0; i<RARRAY_LEN(ary2); i++) {
	VALUE elt = RARRAY_AREF(ary2, i);
	if (!st_update(RHASH_TBL_RAW(hash), (st_data_t)elt, ary_hash_orset, (st_data_t)elt)) {
	    RB_OBJ_WRITTEN(hash, Qundef, elt);
	}
    }
    ary3 = rb_hash_values(hash);
    ary_recycle_hash(hash);
    return ary3;
}