Class: Hash

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

Overview

A Hash is a dictionary-like collection of unique keys and their values. Also called associative arrays, they are similar to Arrays, but where an Array uses integers as its index, a Hash allows you to use any object type.

Hashes enumerate their values in the order that the corresponding keys were inserted.

A Hash can be easily created by using its implicit form:

grades = { "Jane Doe" => 10, "Jim Doe" => 6 }

Hashes allow an alternate syntax form when your keys are always symbols. Instead of

options = { :font_size => 10, :font_family => "Arial" }

You could write it as:

options = { font_size: 10, font_family: "Arial" }

Each named key is a symbol you can access in hash:

options[:font_size]  # => 10

A Hash can also be created through its ::new method:

grades = Hash.new
grades["Dorothy Doe"] = 9

Hashes have a default value that is returned when accessing keys that do not exist in the hash. If no default is set nil is used. You can set the default value by sending it as an argument to Hash.new:

grades = Hash.new(0)

Or by using the #default= method:

grades = {"Timmy Doe" => 8}
grades.default = 0

Accessing a value in a Hash requires using its key:

puts grades["Jane Doe"] # => 10

Common Uses

Hashes are an easy way to represent data structures, such as

books         = {}
books[:matz]  = "The Ruby Language"
books[:black] = "The Well-Grounded Rubyist"

Hashes are also commonly used as a way to have named parameters in functions. Note that no brackets are used below. If a hash is the last argument on a method call, no braces are needed, thus creating a really clean interface:

Person.create(name: "John Doe", age: 27)

def self.create(params)
  @name = params[:name]
  @age  = params[:age]
end

Hash Keys

Two objects refer to the same hash key when their hash value is identical and the two objects are eql? to each other.

A user-defined class may be used as a hash key if the hash and eql? methods are overridden to provide meaningful behavior. By default, separate instances refer to separate hash keys.

A typical implementation of hash is based on the object's data while eql? is usually aliased to the overridden == method:

class Book
  attr_reader :author, :title

  def initialize(author, title)
    @author = author
    @title = title
  end

  def ==(other)
    self.class === other and
      other.author == @author and
      other.title == @title
  end

  alias eql? ==

  def hash
    @author.hash ^ @title.hash # XOR
  end
end

book1 = Book.new 'matz', 'Ruby in a Nutshell'
book2 = Book.new 'matz', 'Ruby in a Nutshell'

reviews = {}

reviews[book1] = 'Great reference!'
reviews[book2] = 'Nice and compact!'

reviews.length #=> 1

See also Object#hash and Object#eql?

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Enumerable

#all?, #any?, #chunk, #collect, #collect_concat, #count, #cycle, #detect, #drop, #drop_while, #each_cons, #each_entry, #each_slice, #each_with_index, #each_with_object, #entries, #find, #find_all, #find_index, #first, #flat_map, #grep, #group_by, #inject, #lazy, #map, #max, #max_by, #min, #min_by, #minmax, #minmax_by, #none?, #one?, #partition, #reduce, #reverse_each, #slice_before, #sort, #sort_by, #take, #take_while, #zip

Constructor Details

#new ⇒ Object #new(obj) ⇒ Object #new {|hash, key| ... } ⇒ Object

Returns a new, empty hash. If this hash is subsequently accessed by a key that doesn't correspond to a hash entry, the value returned depends on the style of new used to create the hash. In the first form, the access returns nil. If obj is specified, this single object will be used for all default values. If a block is specified, it will be called with the hash object and the key, and should return the default value. It is the block's responsibility to store the value in the hash if required.

h = Hash.new("Go Fish")
h["a"] = 100
h["b"] = 200
h["a"]           #=> 100
h["c"]           #=> "Go Fish"
# The following alters the single default object
h["c"].upcase!   #=> "GO FISH"
h["d"]           #=> "GO FISH"
h.keys           #=> ["a", "b"]

# While this creates a new default object each time
h = Hash.new { |hash, key| hash[key] = "Go Fish: #{key}" }
h["c"]           #=> "Go Fish: c"
h["c"].upcase!   #=> "GO FISH: C"
h["d"]           #=> "Go Fish: d"
h.keys           #=> ["c", "d"]

Overloads:



351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
 
# File 'hash.c', line 351

static VALUE
rb_hash_initialize(int argc, VALUE *argv, VALUE hash)
{
    VALUE ifnone;

    rb_hash_modify(hash);
    if (rb_block_given_p()) {
	rb_check_arity(argc, 0, 0);
	ifnone = rb_block_proc();
	default_proc_arity_check(ifnone);
	RHASH_IFNONE(hash) = ifnone;
	FL_SET(hash, HASH_PROC_DEFAULT);
    }
    else {
	rb_scan_args(argc, argv, "01", &ifnone);
	RHASH_IFNONE(hash) = ifnone;
    }

    return hash;
}

Class Method Details

.[](key, value, ...) ⇒ Object .[]([ [key, value)) ⇒ Object .[](object) ⇒ Object

Creates a new hash populated with the given objects. Equivalent to the literal { key => value, ... }. In the first form, keys and values occur in pairs, so there must be an even number of arguments. The second and third form take a single argument which is either an array of key-value pairs or an object convertible to a hash.

Hash["a", 100, "b", 200]             #=> {"a"=>100, "b"=>200}
Hash[ [ ["a", 100], ["b", 200] ] ]   #=> {"a"=>100, "b"=>200}
Hash["a" => 100, "b" => 200]         #=> {"a"=>100, "b"=>200}



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
 
# File 'hash.c', line 389

static VALUE
rb_hash_s_create(int argc, VALUE *argv, VALUE klass)
{
    VALUE hash, tmp;
    int i;

    if (argc == 1) {
	tmp = rb_hash_s_try_convert(Qnil, argv[0]);
	if (!NIL_P(tmp)) {
	    hash = hash_alloc(klass);
	    if (RHASH(tmp)->ntbl) {
		RHASH(hash)->ntbl = st_copy(RHASH(tmp)->ntbl);
	    }
	    return hash;
	}

	tmp = rb_check_array_type(argv[0]);
	if (!NIL_P(tmp)) {
	    long i;

	    hash = hash_alloc(klass);
	    for (i = 0; i < RARRAY_LEN(tmp); ++i) {
		VALUE e = RARRAY_PTR(tmp)[i];
		VALUE v = rb_check_array_type(e);
		VALUE key, val = Qnil;

		if (NIL_P(v)) {
#if 0 /* refix in the next release */
		    rb_raise(rb_eArgError, "wrong element type %s at %ld (expected array)",
			     rb_builtin_class_name(e), i);

#else
		    rb_warn("wrong element type %s at %ld (expected array)",
			    rb_builtin_class_name(e), i);
		    rb_warn("ignoring wrong elements is deprecated, remove them explicitly");
		    rb_warn("this causes ArgumentError in the next release");
		    continue;
#endif
		}
		switch (RARRAY_LEN(v)) {
		  default:
		    rb_raise(rb_eArgError, "invalid number of elements (%ld for 1..2)",
			     RARRAY_LEN(v));
		  case 2:
		    val = RARRAY_PTR(v)[1];
		  case 1:
		    key = RARRAY_PTR(v)[0];
		    rb_hash_aset(hash, key, val);
		}
	    }
	    return hash;
	}
    }
    if (argc % 2 != 0) {
	rb_raise(rb_eArgError, "odd number of arguments for Hash");
    }

    hash = hash_alloc(klass);
    for (i=0; i<argc; i+=2) {
        rb_hash_aset(hash, argv[i], argv[i + 1]);
    }

    return hash;
}

.try_convert(obj) ⇒ Hash?

Try to convert obj into a hash, using to_hash method. Returns converted hash or nil if obj cannot be converted for any reason.

Hash.try_convert({1=>2})   # => {1=>2}
Hash.try_convert("1=>2")   # => nil

Returns:



477
478
479
480
481
 
# File 'hash.c', line 477

static VALUE
rb_hash_s_try_convert(VALUE dummy, VALUE hash)
{
    return rb_check_hash_type(hash);
}

Instance Method Details

#==(other_hash) ⇒ Boolean

Equality---Two hashes are equal if they each contain the same number of keys and if each key-value pair is equal to (according to Object#==) the corresponding elements in the other hash.

h1 = { "a" => 1, "c" => 2 }
h2 = { 7 => 35, "c" => 2, "a" => 1 }
h3 = { "a" => 1, "c" => 2, 7 => 35 }
h4 = { "a" => 1, "d" => 2, "f" => 35 }
h1 == h2   #=> false
h2 == h3   #=> true
h3 == h4   #=> false

Returns:

  • (Boolean) 


1748
1749
1750
1751
1752
 
# File 'hash.c', line 1748

static VALUE
rb_hash_equal(VALUE hash1, VALUE hash2)
{
    return hash_equal(hash1, hash2, FALSE);
}

#[](key) ⇒ Object

Element Reference---Retrieves the value object corresponding to the key object. If not found, returns the default value (see Hash::new for details).

h = { "a" => 100, "b" => 200 }
h["a"]   #=> 100
h["c"]   #=> nil



559
560
561
562
563
564
565
566
567
568
 
# File 'hash.c', line 559

VALUE
rb_hash_aref(VALUE hash, VALUE key)
{
    st_data_t val;

    if (!RHASH(hash)->ntbl || !st_lookup(RHASH(hash)->ntbl, key, &val)) {
	return hash_default_value(hash, key);
    }
    return (VALUE)val;
}

#[]= ⇒ Object

#assoc(obj) ⇒ Array?

Searches through the hash comparing obj with the key using ==. Returns the key-value pair (two elements array) or nil if no match is found. See Array#assoc.

h = {"colors"  => ["red", "blue", "green"],
     "letters" => ["a", "b", "c" ]}
h.assoc("letters")  #=> ["letters", ["a", "b", "c"]]
h.assoc("foo")      #=> nil

Returns:



2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
 
# File 'hash.c', line 2012

VALUE
rb_hash_assoc(VALUE hash, VALUE obj)
{
    VALUE args[2];

    args[0] = obj;
    args[1] = Qnil;
    rb_hash_foreach(hash, assoc_i, (VALUE)args);
    return args[1];
}

#clear ⇒ Hash

Removes all key-value pairs from hsh.

h = { "a" => 100, "b" => 200 }   #=> {"a"=>100, "b"=>200}
h.clear                          #=> {}

Returns:



1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
 
# File 'hash.c', line 1137

VALUE
rb_hash_clear(VALUE hash)
{
    rb_hash_modify_check(hash);
    if (!RHASH(hash)->ntbl)
        return hash;
    if (RHASH(hash)->ntbl->num_entries > 0) {
	if (RHASH_ITER_LEV(hash) > 0)
	    rb_hash_foreach(hash, clear_i, 0);
	else
	    st_clear(RHASH(hash)->ntbl);
    }

    return hash;
}

#compare_by_identity ⇒ Hash

Makes hsh compare its keys by their identity, i.e. it will consider exact same objects as same keys.

h1 = { "a" => 100, "b" => 200, :c => "c" }
h1["a"]        #=> 100
h1.compare_by_identity
h1.compare_by_identity? #=> true
h1["a"]        #=> nil  # different objects.
h1[:c]         #=> "c"  # same symbols are all same.

Returns:



2106
2107
2108
2109
2110
2111
2112
2113
 
# File 'hash.c', line 2106

static VALUE
rb_hash_compare_by_id(VALUE hash)
{
    rb_hash_modify(hash);
    RHASH(hash)->ntbl->type = &identhash;
    rb_hash_rehash(hash);
    return hash;
}

#compare_by_identity? ⇒ Boolean

Returns true if hsh will compare its keys by their identity. Also see Hash#compare_by_identity.

Returns:

  • (Boolean)

Returns:

  • (Boolean) 


2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
 
# File 'hash.c', line 2124

static VALUE
rb_hash_compare_by_id_p(VALUE hash)
{
    if (!RHASH(hash)->ntbl)
        return Qfalse;
    if (RHASH(hash)->ntbl->type == &identhash) {
	return Qtrue;
    }
    return Qfalse;
}

#default(key = nil) ⇒ Object

Returns the default value, the value that would be returned by hsh[key] if key did not exist in hsh. See also Hash::new and Hash#default=.

h = Hash.new                            #=> {}
h.default                               #=> nil
h.default(2)                            #=> nil

h = Hash.new("cat")                     #=> {}
h.default                               #=> "cat"
h.default(2)                            #=> "cat"

h = Hash.new {|h,k| h[k] = k.to_i*10}   #=> {}
h.default                               #=> nil
h.default(2)                            #=> 20

Returns:



671
672
673
674
675
676
677
678
679
680
681
682
683
 
# File 'hash.c', line 671

static VALUE
rb_hash_default(int argc, VALUE *argv, VALUE hash)
{
    VALUE key, ifnone;

    rb_scan_args(argc, argv, "01", &key);
    ifnone = RHASH_IFNONE(hash);
    if (FL_TEST(hash, HASH_PROC_DEFAULT)) {
	if (argc == 0) return Qnil;
	return rb_funcall(ifnone, id_yield, 2, hash, key);
    }
    return ifnone;
}

#default=(obj) ⇒ Object

Sets the default value, the value returned for a key that does not exist in the hash. It is not possible to set the default to a Proc that will be executed on each key lookup.

h = { "a" => 100, "b" => 200 }
h.default = "Go fish"
h["a"]     #=> 100
h["z"]     #=> "Go fish"
# This doesn't do what you might hope...
h.default = proc do |hash, key|
  hash[key] = key + key
end
h[2]       #=> #<Proc:0x401b3948@-:6>
h["cat"]   #=> #<Proc:0x401b3948@-:6>

Returns:



705
706
707
708
709
710
711
712
 
# File 'hash.c', line 705

static VALUE
rb_hash_set_default(VALUE hash, VALUE ifnone)
{
    rb_hash_modify_check(hash);
    RHASH_IFNONE(hash) = ifnone;
    FL_UNSET(hash, HASH_PROC_DEFAULT);
    return ifnone;
}

#default_proc ⇒ Object

If Hash::new was invoked with a block, return that block, otherwise return nil.

h = Hash.new {|h,k| h[k] = k*k }   #=> {}
p = h.default_proc                 #=> #<Proc:0x401b3d08@-:1>
a = []                             #=> []
p.call(a, 2)
a                                  #=> [nil, nil, 4]

Returns:



729
730
731
732
733
734
735
736
 
# File 'hash.c', line 729

static VALUE
rb_hash_default_proc(VALUE hash)
{
    if (FL_TEST(hash, HASH_PROC_DEFAULT)) {
	return RHASH_IFNONE(hash);
    }
    return Qnil;
}

#default_proc=(proc_obj) ⇒ Object

Sets the default proc to be executed on each failed key lookup.

h.default_proc = proc do |hash, key|
  hash[key] = key + key
end
h[2]       #=> 4
h["cat"]   #=> "catcat"



751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
 
# File 'hash.c', line 751

static VALUE
rb_hash_set_default_proc(VALUE hash, VALUE proc)
{
    VALUE b;

    rb_hash_modify_check(hash);
    if (NIL_P(proc)) {
	FL_UNSET(hash, HASH_PROC_DEFAULT);
	RHASH_IFNONE(hash) = proc;
	return proc;
    }
    b = rb_check_convert_type(proc, T_DATA, "Proc", "to_proc");
    if (NIL_P(b) || !rb_obj_is_proc(b)) {
	rb_raise(rb_eTypeError,
		 "wrong default_proc type %s (expected Proc)",
		 rb_obj_classname(proc));
    }
    proc = b;
    default_proc_arity_check(proc);
    RHASH_IFNONE(hash) = proc;
    FL_SET(hash, HASH_PROC_DEFAULT);
    return proc;
}

#delete(key) ⇒ Object #delete(key) {|key| ... } ⇒ Object

Deletes the key-value pair and returns the value from hsh whose key is equal to key. If the key is not found, returns the default value. If the optional code block is given and the key is not found, pass in the key and return the result of block.

h = { "a" => 100, "b" => 200 }
h.delete("a")                              #=> 100
h.delete("z")                              #=> nil
h.delete("z") { |el| "#{el} not found" }   #=> "z not found"

Overloads:

  • #delete(key) {|key| ... } ⇒ Object

    Yields:



858
859
860
861
862
863
864
865
866
867
868
869
870
 
# File 'hash.c', line 858

VALUE
rb_hash_delete(VALUE hash, VALUE key)
{
    VALUE val;

    rb_hash_modify_check(hash);
    val = rb_hash_delete_key(hash, key);
    if (val != Qundef) return val;
    if (rb_block_given_p()) {
	return rb_yield(key);
    }
    return Qnil;
}

#delete_if {|key, value| ... } ⇒ Hash #delete_if ⇒ Object

Deletes every key-value pair from hsh for which block evaluates to true.

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

h = { "a" => 100, "b" => 200, "c" => 300 }
h.delete_if {|key, value| key >= "b" }   #=> {"a"=>100}

Overloads:

  • #delete_if {|key, value| ... } ⇒ Hash

    Yields:

    Returns:



958
959
960
961
962
963
964
965
966
 
# File 'hash.c', line 958

VALUE
rb_hash_delete_if(VALUE hash)
{
    RETURN_SIZED_ENUMERATOR(hash, 0, 0, rb_hash_size);
    rb_hash_modify_check(hash);
    if (RHASH(hash)->ntbl)
	rb_hash_foreach(hash, delete_if_i, hash);
    return hash;
}

#each {|key, value| ... } ⇒ Hash #each_pair {|key, value| ... } ⇒ Hash #each ⇒ Object #each_pair ⇒ Object

Calls block once for each key in hsh, passing the key-value pair as parameters.

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

h = { "a" => 100, "b" => 200 }
h.each {|key, value| puts "#{key} is #{value}" }

produces:

a is 100
b is 200

Overloads:

  • #each {|key, value| ... } ⇒ Hash

    Yields:

    Returns:

  • #each_pair {|key, value| ... } ⇒ Hash

    Yields:

    Returns:



1409
1410
1411
1412
1413
1414
1415
 
# File 'hash.c', line 1409

static VALUE
rb_hash_each_pair(VALUE hash)
{
    RETURN_SIZED_ENUMERATOR(hash, 0, 0, rb_hash_size);
    rb_hash_foreach(hash, each_pair_i, 0);
    return hash;
}

#each_key {|key| ... } ⇒ Hash #each_key ⇒ Object

Calls block once for each key in hsh, passing the key as a parameter.

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

h = { "a" => 100, "b" => 200 }
h.each_key {|key| puts key }

produces:

a
b

Overloads:

  • #each_key {|key| ... } ⇒ Hash

    Yields:

    Returns:



1372
1373
1374
1375
1376
1377
1378
 
# File 'hash.c', line 1372

static VALUE
rb_hash_each_key(VALUE hash)
{
    RETURN_SIZED_ENUMERATOR(hash, 0, 0, rb_hash_size);
    rb_hash_foreach(hash, each_key_i, 0);
    return hash;
}

#each {|key, value| ... } ⇒ Hash #each_pair {|key, value| ... } ⇒ Hash #each ⇒ Object #each_pair ⇒ Object

Calls block once for each key in hsh, passing the key-value pair as parameters.

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

h = { "a" => 100, "b" => 200 }
h.each {|key, value| puts "#{key} is #{value}" }

produces:

a is 100
b is 200

Overloads:

  • #each {|key, value| ... } ⇒ Hash

    Yields:

    Returns:

  • #each_pair {|key, value| ... } ⇒ Hash

    Yields:

    Returns:



1409
1410
1411
1412
1413
1414
1415
 
# File 'hash.c', line 1409

static VALUE
rb_hash_each_pair(VALUE hash)
{
    RETURN_SIZED_ENUMERATOR(hash, 0, 0, rb_hash_size);
    rb_hash_foreach(hash, each_pair_i, 0);
    return hash;
}

#each_value {|value| ... } ⇒ Hash #each_value ⇒ Object

Calls block once for each key in hsh, passing the value as a parameter.

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

h = { "a" => 100, "b" => 200 }
h.each_value {|value| puts value }

produces:

100
200

Overloads:

  • #each_value {|value| ... } ⇒ Hash

    Yields:

    • (value)

    Returns:



1339
1340
1341
1342
1343
1344
1345
 
# File 'hash.c', line 1339

static VALUE
rb_hash_each_value(VALUE hash)
{
    RETURN_SIZED_ENUMERATOR(hash, 0, 0, rb_hash_size);
    rb_hash_foreach(hash, each_value_i, 0);
    return hash;
}

#empty? ⇒ Boolean

Returns true if hsh contains no key-value pairs.

{}.empty?   #=> true

Returns:

  • (Boolean)

Returns:

  • (Boolean) 


1307
1308
1309
1310
1311
 
# File 'hash.c', line 1307

static VALUE
rb_hash_empty_p(VALUE hash)
{
    return RHASH_EMPTY_P(hash) ? Qtrue : Qfalse;
}

#eql?(other) ⇒ Boolean

Returns true if hash and other are both hashes with the same content.

Returns:

  • (Boolean)

Returns:

  • (Boolean) 


1762
1763
1764
1765
1766
 
# File 'hash.c', line 1762

static VALUE
rb_hash_eql(VALUE hash1, VALUE hash2)
{
    return hash_equal(hash1, hash2, TRUE);
}

#fetch(key[, default]) ⇒ Object #fetch(key) {|key| ... } ⇒ Object

Returns a value from the hash for the given key. If the key can't be found, there are several options: With no other arguments, it will raise an KeyError exception; if default is given, then that will be returned; if the optional code block is specified, then that will be run and its result returned.

h = { "a" => 100, "b" => 200 }
h.fetch("a")                            #=> 100
h.fetch("z", "go fish")                 #=> "go fish"
h.fetch("z") { |el| "go fish, #{el}"}   #=> "go fish, z"

The following example shows that an exception is raised if the key is not found and a default value is not supplied.

h = { "a" => 100, "b" => 200 }
h.fetch("z")

produces:

prog.rb:2:in `fetch': key not found (KeyError)
 from prog.rb:2

Overloads:



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
 
# File 'hash.c', line 616

static VALUE
rb_hash_fetch_m(int argc, VALUE *argv, VALUE hash)
{
    VALUE key, if_none;
    st_data_t val;
    long block_given;

    rb_scan_args(argc, argv, "11", &key, &if_none);

    block_given = rb_block_given_p();
    if (block_given && argc == 2) {
	rb_warn("block supersedes default value argument");
    }
    if (!RHASH(hash)->ntbl || !st_lookup(RHASH(hash)->ntbl, key, &val)) {
	if (block_given) return rb_yield(key);
	if (argc == 1) {
	    volatile VALUE desc = rb_protect(rb_inspect, key, 0);
	    if (NIL_P(desc)) {
		desc = rb_any_to_s(key);
	    }
	    desc = rb_str_ellipsize(desc, 65);
	    rb_raise(rb_eKeyError, "key not found: %s", RSTRING_PTR(desc));
	}
	return if_none;
    }
    return (VALUE)val;
}

#flatten ⇒ Array #flatten(level) ⇒ Array

Returns a new array that is a one-dimensional flattening of this hash. That is, for every key or value that is an array, extract its elements into the new array. Unlike Array#flatten, this method does not flatten recursively by default. The optional level argument determines the level of recursion to flatten.

a =  {1=> "one", 2 => [2,"two"], 3 => "three"}
a.flatten    # => [1, "one", 2, [2, "two"], 3, "three"]
a.flatten(2) # => [1, "one", 2, 2, "two", 3, "three"]

Overloads:



2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
 
# File 'hash.c', line 2075

static VALUE
rb_hash_flatten(int argc, VALUE *argv, VALUE hash)
{
    VALUE ary, tmp;

    ary = rb_hash_to_a(hash);
    if (argc == 0) {
	argc = 1;
	tmp = INT2FIX(1);
	argv = &tmp;
    }
    rb_funcall2(ary, rb_intern("flatten!"), argc, argv);
    return ary;
}

#has_key?(key) ⇒ Boolean #include?(key) ⇒ Boolean #key?(key) ⇒ Boolean #member?(key) ⇒ Boolean

Returns true if the given key is present in hsh.

h = { "a" => 100, "b" => 200 }
h.has_key?("a")   #=> true
h.has_key?("z")   #=> false

Overloads:

  • #has_key?(key) ⇒ Boolean

    Returns:

    • (Boolean)
  • #include?(key) ⇒ Boolean

    Returns:

    • (Boolean)
  • #key?(key) ⇒ Boolean

    Returns:

    • (Boolean)
  • #member?(key) ⇒ Boolean

    Returns:

    • (Boolean)

Returns:

  • (Boolean) 


1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
 
# File 'hash.c', line 1614

static VALUE
rb_hash_has_key(VALUE hash, VALUE key)
{
    if (!RHASH(hash)->ntbl)
        return Qfalse;
    if (st_lookup(RHASH(hash)->ntbl, key, 0)) {
	return Qtrue;
    }
    return Qfalse;
}

#has_value?(value) ⇒ Boolean #value?(value) ⇒ Boolean

Returns true if the given value is present for some key in hsh.

h = { "a" => 100, "b" => 200 }
h.has_value?(100)   #=> true
h.has_value?(999)   #=> false

Overloads:

  • #has_value?(value) ⇒ Boolean

    Returns:

    • (Boolean)
  • #value?(value) ⇒ Boolean

    Returns:

    • (Boolean)

Returns:

  • (Boolean) 


1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
 
# File 'hash.c', line 1650

static VALUE
rb_hash_has_value(VALUE hash, VALUE val)
{
    VALUE data[2];

    data[0] = Qfalse;
    data[1] = val;
    rb_hash_foreach(hash, rb_hash_search_value, (VALUE)data);
    return data[0];
}

#hash ⇒ Fixnum

Compute a hash-code for this hash. Two hashes with the same content will have the same hash code (and will compare using eql?).

Returns:



1805
1806
1807
1808
1809
 
# File 'hash.c', line 1805

static VALUE
rb_hash_hash(VALUE hash)
{
    return rb_exec_recursive_outer(recursive_hash, hash, 0);
}

#has_key?(key) ⇒ Boolean #include?(key) ⇒ Boolean #key?(key) ⇒ Boolean #member?(key) ⇒ Boolean

Returns true if the given key is present in hsh.

h = { "a" => 100, "b" => 200 }
h.has_key?("a")   #=> true
h.has_key?("z")   #=> false

Overloads:

  • #has_key?(key) ⇒ Boolean

    Returns:

    • (Boolean)
  • #include?(key) ⇒ Boolean

    Returns:

    • (Boolean)
  • #key?(key) ⇒ Boolean

    Returns:

    • (Boolean)
  • #member?(key) ⇒ Boolean

    Returns:

    • (Boolean)

Returns:

  • (Boolean) 


1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
 
# File 'hash.c', line 1614

static VALUE
rb_hash_has_key(VALUE hash, VALUE key)
{
    if (!RHASH(hash)->ntbl)
        return Qfalse;
    if (st_lookup(RHASH(hash)->ntbl, key, 0)) {
	return Qtrue;
    }
    return Qfalse;
}

#index ⇒ Object

:nodoc:



815
816
817
818
819
820
 
# File 'hash.c', line 815

static VALUE
rb_hash_index(VALUE hash, VALUE value)
{
    rb_warn("Hash#index is deprecated; use Hash#key");
    return rb_hash_key(hash, value);
}

#initialize_copy ⇒ Object 



1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
 
# File 'hash.c', line 1216

static VALUE
rb_hash_initialize_copy(VALUE hash, VALUE hash2)
{
    rb_hash_modify_check(hash);
    hash2 = to_hash(hash2);

    Check_Type(hash2, T_HASH);

    if (!RHASH_EMPTY_P(hash2)) {
        RHASH(hash)->ntbl = st_copy(RHASH(hash2)->ntbl);
	rb_hash_rehash(hash);
    }

    if (FL_TEST(hash2, HASH_PROC_DEFAULT)) {
        FL_SET(hash, HASH_PROC_DEFAULT);
    }
    else {
	FL_UNSET(hash, HASH_PROC_DEFAULT);
    }
    RHASH_IFNONE(hash) = RHASH_IFNONE(hash2);

    return hash;
}

#to_s ⇒ String #inspect ⇒ String Also known as: to_s

Return the contents of this hash as a string.

h = { "c" => 300, "a" => 100, "d" => 400, "c" => 300  }
h.to_s   #=> "{\"c\"=>300, \"a\"=>100, \"d\"=>400}"

Overloads:



1494
1495
1496
1497
1498
1499
1500
 
# File 'hash.c', line 1494

static VALUE
rb_hash_inspect(VALUE hash)
{
    if (RHASH_EMPTY_P(hash))
	return rb_usascii_str_new2("{}");
    return rb_exec_recursive(inspect_hash, hash, 0);
}

#invert ⇒ Object

Returns a new hash created by using hsh's values as keys, and the keys as values.

h = { "n" => 100, "m" => 100, "y" => 300, "d" => 200, "a" => 0 }
h.invert   #=> {0=>"a", 100=>"m", 200=>"d", 300=>"y"}



1830
1831
1832
1833
1834
1835
1836
1837
 
# File 'hash.c', line 1830

static VALUE
rb_hash_invert(VALUE hash)
{
    VALUE h = rb_hash_new();

    rb_hash_foreach(hash, rb_hash_invert_i, h);
    return h;
}

#keep_if {|key, value| ... } ⇒ Hash #keep_if ⇒ Object

Deletes every key-value pair from hsh for which block evaluates to false.

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

Overloads:

  • #keep_if {|key, value| ... } ⇒ Hash

    Yields:

    Returns:



1110
1111
1112
1113
1114
1115
1116
1117
1118
 
# File 'hash.c', line 1110

VALUE
rb_hash_keep_if(VALUE hash)
{
    RETURN_SIZED_ENUMERATOR(hash, 0, 0, rb_hash_size);
    rb_hash_modify_check(hash);
    if (RHASH(hash)->ntbl)
	rb_hash_foreach(hash, keep_if_i, hash);
    return hash;
}

#key(value) ⇒ Object

Returns the key of an occurrence of a given value. If the value is not found, returns nil.

h = { "a" => 100, "b" => 200, "c" => 300, "d" => 300 }
h.key(200)   #=> "b"
h.key(300)   #=> "c"
h.key(999)   #=> nil



801
802
803
804
805
806
807
808
809
810
811
812
 
# File 'hash.c', line 801

static VALUE
rb_hash_key(VALUE hash, VALUE value)
{
    VALUE args[2];

    args[0] = value;
    args[1] = Qnil;

    rb_hash_foreach(hash, key_i, (VALUE)args);

    return args[1];
}

#has_key?(key) ⇒ Boolean #include?(key) ⇒ Boolean #key?(key) ⇒ Boolean #member?(key) ⇒ Boolean

Returns true if the given key is present in hsh.

h = { "a" => 100, "b" => 200 }
h.has_key?("a")   #=> true
h.has_key?("z")   #=> false

Overloads:

  • #has_key?(key) ⇒ Boolean

    Returns:

    • (Boolean)
  • #include?(key) ⇒ Boolean

    Returns:

    • (Boolean)
  • #key?(key) ⇒ Boolean

    Returns:

    • (Boolean)
  • #member?(key) ⇒ Boolean

    Returns:

    • (Boolean)

Returns:

  • (Boolean) 


1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
 
# File 'hash.c', line 1614

static VALUE
rb_hash_has_key(VALUE hash, VALUE key)
{
    if (!RHASH(hash)->ntbl)
        return Qfalse;
    if (st_lookup(RHASH(hash)->ntbl, key, 0)) {
	return Qtrue;
    }
    return Qfalse;
}

#keys ⇒ Array

Returns a new array populated with the keys from this hash. See also Hash#values.

h = { "a" => 100, "b" => 200, "c" => 300, "d" => 400 }
h.keys   #=> ["a", "b", "c", "d"]

Returns:



1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
 
# File 'hash.c', line 1558

static VALUE
rb_hash_keys(VALUE hash)
{
    VALUE ary;

    ary = rb_ary_new();
    rb_hash_foreach(hash, keys_i, ary);

    return ary;
}

#length ⇒ Fixnum #size ⇒ Fixnum

Returns the number of key-value pairs in the hash.

h = { "d" => 100, "a" => 200, "v" => 300, "e" => 400 }
h.length        #=> 4
h.delete("a")   #=> 200
h.length        #=> 3

Overloads:



1288
1289
1290
1291
1292
1293
1294
 
# File 'hash.c', line 1288

static VALUE
rb_hash_size(VALUE hash)
{
    if (!RHASH(hash)->ntbl)
        return INT2FIX(0);
    return INT2FIX(RHASH(hash)->ntbl->num_entries);
}

#has_key?(key) ⇒ Boolean #include?(key) ⇒ Boolean #key?(key) ⇒ Boolean #member?(key) ⇒ Boolean

Returns true if the given key is present in hsh.

h = { "a" => 100, "b" => 200 }
h.has_key?("a")   #=> true
h.has_key?("z")   #=> false

Overloads:

  • #has_key?(key) ⇒ Boolean

    Returns:

    • (Boolean)
  • #include?(key) ⇒ Boolean

    Returns:

    • (Boolean)
  • #key?(key) ⇒ Boolean

    Returns:

    • (Boolean)
  • #member?(key) ⇒ Boolean

    Returns:

    • (Boolean)

Returns:

  • (Boolean) 


1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
 
# File 'hash.c', line 1614

static VALUE
rb_hash_has_key(VALUE hash, VALUE key)
{
    if (!RHASH(hash)->ntbl)
        return Qfalse;
    if (st_lookup(RHASH(hash)->ntbl, key, 0)) {
	return Qtrue;
    }
    return Qfalse;
}

#merge(other_hash) ⇒ Object #merge(other_hash) {|key, oldval, newval| ... } ⇒ Object

Returns a new hash containing the contents of other_hash and the contents of hsh. If no block is specified, the value for entries with duplicate keys will be that of other_hash. Otherwise the value for each duplicate key is determined by calling the block with the key, its value in hsh and its value in other_hash.

h1 = { "a" => 100, "b" => 200 }
h2 = { "b" => 254, "c" => 300 }
h1.merge(h2)   #=> {"a"=>100, "b"=>254, "c"=>300}
h1.merge(h2){|key, oldval, newval| newval - oldval}
               #=> {"a"=>100, "b"=>54,  "c"=>300}
h1             #=> {"a"=>100, "b"=>200}

Overloads:

  • #merge(other_hash) {|key, oldval, newval| ... } ⇒ Object

    Yields:

    • (key, oldval, newval) 


1980
1981
1982
1983
1984
 
# File 'hash.c', line 1980

static VALUE
rb_hash_merge(VALUE hash1, VALUE hash2)
{
    return rb_hash_update(rb_obj_dup(hash1), hash2);
}

#merge!(other_hash) ⇒ Hash #update(other_hash) ⇒ Hash #merge!(other_hash) {|key, oldval, newval| ... } ⇒ Hash #update(other_hash) {|key, oldval, newval| ... } ⇒ Hash

Adds the contents of other_hash to hsh. If no block is specified, entries with duplicate keys are overwritten with the values from other_hash, otherwise the value of each duplicate key is determined by calling the block with the key, its value in hsh and its value in other_hash.

h1 = { "a" => 100, "b" => 200 }
h2 = { "b" => 254, "c" => 300 }
h1.merge!(h2)   #=> {"a"=>100, "b"=>254, "c"=>300}

h1 = { "a" => 100, "b" => 200 }
h2 = { "b" => 254, "c" => 300 }
h1.merge!(h2) { |key, v1, v2| v1 }
                #=> {"a"=>100, "b"=>200, "c"=>300}

Overloads:

  • #merge!(other_hash) ⇒ Hash

    Returns:

  • #update(other_hash) ⇒ Hash

    Returns:

  • #merge!(other_hash) {|key, oldval, newval| ... } ⇒ Hash

    Yields:

    • (key, oldval, newval)

    Returns:

  • #update(other_hash) {|key, oldval, newval| ... } ⇒ Hash

    Yields:

    • (key, oldval, newval)

    Returns:



1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
 
# File 'hash.c', line 1898

static VALUE
rb_hash_update(VALUE hash1, VALUE hash2)
{
    rb_hash_modify(hash1);
    hash2 = to_hash(hash2);
    if (rb_block_given_p()) {
	rb_hash_foreach(hash2, rb_hash_update_block_i, hash1);
    }
    else {
	rb_hash_foreach(hash2, rb_hash_update_i, hash1);
    }
    return hash1;
}

#rassoc(obj) ⇒ Array?

Searches through the hash comparing obj with the value using ==. Returns the first key-value pair (two-element array) that matches. See also Array#rassoc.

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

Returns:



2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
 
# File 'hash.c', line 2048

VALUE
rb_hash_rassoc(VALUE hash, VALUE obj)
{
    VALUE args[2];

    args[0] = obj;
    args[1] = Qnil;
    rb_hash_foreach(hash, rassoc_i, (VALUE)args);
    return args[1];
}

#rehash ⇒ Hash

Rebuilds the hash based on the current hash values for each key. If values of key objects have changed since they were inserted, this method will reindex hsh. If Hash#rehash is called while an iterator is traversing the hash, an RuntimeError will be raised in the iterator.

a = [ "a", "b" ]
c = [ "c", "d" ]
h = { a => 100, c => 300 }
h[a]       #=> 100
a[0] = "z"
h[a]       #=> nil
h.rehash   #=> {["z", "b"]=>100, ["c", "d"]=>300}
h[a]       #=> 100

Returns:



512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
 
# File 'hash.c', line 512

static VALUE
rb_hash_rehash(VALUE hash)
{
    st_table *tbl;

    if (RHASH_ITER_LEV(hash) > 0) {
	rb_raise(rb_eRuntimeError, "rehash during iteration");
    }
    rb_hash_modify_check(hash);
    if (!RHASH(hash)->ntbl)
        return hash;
    tbl = st_init_table_with_size(RHASH(hash)->ntbl->type, RHASH(hash)->ntbl->num_entries);
    rb_hash_foreach(hash, rb_hash_rehash_i, (VALUE)tbl);
    st_free_table(RHASH(hash)->ntbl);
    RHASH(hash)->ntbl = tbl;

    return hash;
}

#reject {|key, value| ... } ⇒ Hash #reject ⇒ Object

Same as Hash#delete_if, but works on (and returns) a copy of the hsh. Equivalent to hsh.dup.delete_if.

Overloads:

  • #reject {|key, value| ... } ⇒ Hash

    Yields:

    Returns:



1003
1004
1005
1006
1007
 
# File 'hash.c', line 1003

static VALUE
rb_hash_reject(VALUE hash)
{
    return rb_hash_delete_if(rb_obj_dup(hash));
}

#reject! {|key, value| ... } ⇒ Hash? #reject! ⇒ Object

Equivalent to Hash#delete_if, but returns nil if no changes were made.

Overloads:

  • #reject! {|key, value| ... } ⇒ Hash?

    Yields:

    Returns:



977
978
979
980
981
982
983
984
985
986
987
988
989
990
 
# File 'hash.c', line 977

VALUE
rb_hash_reject_bang(VALUE hash)
{
    st_index_t n;

    RETURN_SIZED_ENUMERATOR(hash, 0, 0, rb_hash_size);
    rb_hash_modify(hash);
    if (!RHASH(hash)->ntbl)
        return Qnil;
    n = RHASH(hash)->ntbl->num_entries;
    rb_hash_foreach(hash, delete_if_i, hash);
    if (n == RHASH(hash)->ntbl->num_entries) return Qnil;
    return hash;
}

#replace(other_hash) ⇒ Hash

Replaces the contents of hsh with the contents of other_hash.

h = { "a" => 100, "b" => 200 }
h.replace({ "c" => 300, "d" => 400 })   #=> {"c"=>300, "d"=>400}

Returns:



1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
 
# File 'hash.c', line 1252

static VALUE
rb_hash_replace(VALUE hash, VALUE hash2)
{
    rb_hash_modify_check(hash);
    hash2 = to_hash(hash2);
    if (hash == hash2) return hash;
    rb_hash_clear(hash);
    if (RHASH(hash2)->ntbl) {
	rb_hash_tbl(hash);
	RHASH(hash)->ntbl->type = RHASH(hash2)->ntbl->type;
    }
    rb_hash_foreach(hash2, replace_i, hash);
    RHASH_IFNONE(hash) = RHASH_IFNONE(hash2);
    if (FL_TEST(hash2, HASH_PROC_DEFAULT)) {
	FL_SET(hash, HASH_PROC_DEFAULT);
    }
    else {
	FL_UNSET(hash, HASH_PROC_DEFAULT);
    }

    return hash;
}

#select {|key, value| ... } ⇒ Hash #select ⇒ Object

Returns a new hash consisting of entries for which the block returns true.

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

h = { "a" => 100, "b" => 200, "c" => 300 }
h.select {|k,v| k > "a"}  #=> {"b" => 200, "c" => 300}
h.select {|k,v| v < 200}  #=> {"a" => 100}

Overloads:

  • #select {|key, value| ... } ⇒ Hash

    Yields:

    Returns:



1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
 
# File 'hash.c', line 1054

VALUE
rb_hash_select(VALUE hash)
{
    VALUE result;

    RETURN_SIZED_ENUMERATOR(hash, 0, 0, rb_hash_size);
    result = rb_hash_new();
    rb_hash_foreach(hash, select_i, result);
    return result;
}

#select! {|key, value| ... } ⇒ Hash? #select! ⇒ Object

Equivalent to Hash#keep_if, but returns nil if no changes were made.

Overloads:

  • #select! {|key, value| ... } ⇒ Hash?

    Yields:

    Returns:



1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
 
# File 'hash.c', line 1083

VALUE
rb_hash_select_bang(VALUE hash)
{
    st_index_t n;

    RETURN_SIZED_ENUMERATOR(hash, 0, 0, rb_hash_size);
    rb_hash_modify_check(hash);
    if (!RHASH(hash)->ntbl)
        return Qnil;
    n = RHASH(hash)->ntbl->num_entries;
    rb_hash_foreach(hash, keep_if_i, hash);
    if (n == RHASH(hash)->ntbl->num_entries) return Qnil;
    return hash;
}

#shift ⇒ Array, Object

Removes a key-value pair from hsh and returns it as the two-item array [ key, value ], or the hash's default value if the hash is empty.

h = { 1 => "a", 2 => "b", 3 => "c" }
h.shift   #=> [1, "a"]
h         #=> {2=>"b", 3=>"c"}

Returns:



911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
 
# File 'hash.c', line 911

static VALUE
rb_hash_shift(VALUE hash)
{
    struct shift_var var;

    rb_hash_modify_check(hash);
    if (RHASH(hash)->ntbl) {
	var.key = Qundef;
	rb_hash_foreach(hash, RHASH_ITER_LEV(hash) > 0 ? shift_i_safe : shift_i,
			(VALUE)&var);

	if (var.key != Qundef) {
	    if (RHASH_ITER_LEV(hash) > 0) {
		rb_hash_delete_key(hash, var.key);
	    }
	    return rb_assoc_new(var.key, var.val);
	}
    }
    return hash_default_value(hash, Qnil);
}

#length ⇒ Fixnum #size ⇒ Fixnum

Returns the number of key-value pairs in the hash.

h = { "d" => 100, "a" => 200, "v" => 300, "e" => 400 }
h.length        #=> 4
h.delete("a")   #=> 200
h.length        #=> 3

Overloads:



1288
1289
1290
1291
1292
1293
1294
 
# File 'hash.c', line 1288

static VALUE
rb_hash_size(VALUE hash)
{
    if (!RHASH(hash)->ntbl)
        return INT2FIX(0);
    return INT2FIX(RHASH(hash)->ntbl->num_entries);
}

#store ⇒ Object

#to_a ⇒ Array

Converts hsh to a nested array of [ key, value ] arrays.

h = { "c" => 300, "a" => 100, "d" => 400, "c" => 300  }
h.to_a   #=> [["c", 300], ["a", 100], ["d", 400]]

Returns:



1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
 
# File 'hash.c', line 1435

static VALUE
rb_hash_to_a(VALUE hash)
{
    VALUE ary;

    ary = rb_ary_new();
    rb_hash_foreach(hash, to_a_i, ary);
    OBJ_INFECT(ary, hash);

    return ary;
}

#to_h ⇒ Hash

Returns self. If called on a subclass of Hash, converts the receiver to a Hash object.

Returns:



1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
 
# File 'hash.c', line 1523

static VALUE
rb_hash_to_h(VALUE hash)
{
    if (rb_obj_class(hash) != rb_cHash) {
	VALUE ret = rb_hash_new();
	if (!RHASH_EMPTY_P(hash))
	    RHASH(ret)->ntbl = st_copy(RHASH(hash)->ntbl);
	if (FL_TEST(hash, HASH_PROC_DEFAULT)) {
	    FL_SET(ret, HASH_PROC_DEFAULT);
	}
	RHASH_IFNONE(ret) = RHASH_IFNONE(hash);
	return ret;
    }
    return hash;
}

#to_hash ⇒ Hash

Returns self.

Returns:



1509
1510
1511
1512
1513
 
# File 'hash.c', line 1509

static VALUE
rb_hash_to_hash(VALUE hash)
{
    return hash;
}

#merge!(other_hash) ⇒ Hash #update(other_hash) ⇒ Hash #merge!(other_hash) {|key, oldval, newval| ... } ⇒ Hash #update(other_hash) {|key, oldval, newval| ... } ⇒ Hash

Adds the contents of other_hash to hsh. If no block is specified, entries with duplicate keys are overwritten with the values from other_hash, otherwise the value of each duplicate key is determined by calling the block with the key, its value in hsh and its value in other_hash.

h1 = { "a" => 100, "b" => 200 }
h2 = { "b" => 254, "c" => 300 }
h1.merge!(h2)   #=> {"a"=>100, "b"=>254, "c"=>300}

h1 = { "a" => 100, "b" => 200 }
h2 = { "b" => 254, "c" => 300 }
h1.merge!(h2) { |key, v1, v2| v1 }
                #=> {"a"=>100, "b"=>200, "c"=>300}

Overloads:

  • #merge!(other_hash) ⇒ Hash

    Returns:

  • #update(other_hash) ⇒ Hash

    Returns:

  • #merge!(other_hash) {|key, oldval, newval| ... } ⇒ Hash

    Yields:

    • (key, oldval, newval)

    Returns:

  • #update(other_hash) {|key, oldval, newval| ... } ⇒ Hash

    Yields:

    • (key, oldval, newval)

    Returns:



1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
 
# File 'hash.c', line 1898

static VALUE
rb_hash_update(VALUE hash1, VALUE hash2)
{
    rb_hash_modify(hash1);
    hash2 = to_hash(hash2);
    if (rb_block_given_p()) {
	rb_hash_foreach(hash2, rb_hash_update_block_i, hash1);
    }
    else {
	rb_hash_foreach(hash2, rb_hash_update_i, hash1);
    }
    return hash1;
}

#has_value?(value) ⇒ Boolean #value?(value) ⇒ Boolean

Returns true if the given value is present for some key in hsh.

h = { "a" => 100, "b" => 200 }
h.has_value?(100)   #=> true
h.has_value?(999)   #=> false

Overloads:

  • #has_value?(value) ⇒ Boolean

    Returns:

    • (Boolean)
  • #value?(value) ⇒ Boolean

    Returns:

    • (Boolean)

Returns:

  • (Boolean) 


1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
 
# File 'hash.c', line 1650

static VALUE
rb_hash_has_value(VALUE hash, VALUE val)
{
    VALUE data[2];

    data[0] = Qfalse;
    data[1] = val;
    rb_hash_foreach(hash, rb_hash_search_value, (VALUE)data);
    return data[0];
}

#values ⇒ Array

Returns a new array populated with the values from hsh. See also Hash#keys.

h = { "a" => 100, "b" => 200, "c" => 300 }
h.values   #=> [100, 200, 300]

Returns:



1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
 
# File 'hash.c', line 1588

static VALUE
rb_hash_values(VALUE hash)
{
    VALUE ary;

    ary = rb_ary_new();
    rb_hash_foreach(hash, values_i, ary);

    return ary;
}

#values_at(key, ...) ⇒ Array

Return an array containing the values associated with the given keys. Also see Hash.select.

h = { "cat" => "feline", "dog" => "canine", "cow" => "bovine" }
h.values_at("cow", "cat")  #=> ["bovine", "feline"]

Returns:



1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
 
# File 'hash.c', line 1020

VALUE
rb_hash_values_at(int argc, VALUE *argv, VALUE hash)
{
    VALUE result = rb_ary_new2(argc);
    long i;

    for (i=0; i<argc; i++) {
	rb_ary_push(result, rb_hash_aref(hash, argv[i]));
    }
    return result;
}