Class: Hash

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

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Enumerable

#all?, #any?, #collect, #count, #cycle, #detect, #drop, #drop_while, #each_cons, #each_slice, #each_with_index, #entries, #enum_cons, #enum_slice, #enum_with_index, #find, #find_all, #find_index, #first, #grep, #group_by, #inject, #map, #max, #max_by, #min, #min_by, #minmax, #minmax_by, #none?, #one?, #partition, #reduce, #reverse_each, #sort_by, #take, #take_while, #zip

Constructor Details

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

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:

  • #new {|hash, key| ... } ⇒ Hash

    Yields:



# File 'hash.c'

/*
 *  call-seq:
 *     Hash.new                          => hash
 *     Hash.new(obj)                     => aHash
 *     Hash.new {|hash, key| block }     => aHash
 *
 *  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 <code>new</code> used to create the hash. In
 *  the first form, the access returns <code>nil</code>. If
 *  <i>obj</i> is specified, this single object will be used for
 *  all <em>default values</em>. 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"]
 *
 */

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

    rb_hash_modify(hash);
    if (rb_block_given_p()) {
    if (argc > 0) {
        rb_raise(rb_eArgError, "wrong number of arguments");
    }
    RHASH(hash)->ifnone = rb_block_proc();
    FL_SET(hash, HASH_PROC_DEFAULT);
    }
    else {
    rb_scan_args(argc, argv, "01", &ifnone);
    RHASH(hash)->ifnone = ifnone;
    }

    return hash;
}

Class Method Details

.[]([key = >|, value)) ⇒ Hash

Creates a new hash populated with the given objects. Equivalent to the literal { key, value, ... }. Keys and values occur in pairs, so there must be an even number of arguments.

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


# File 'hash.c'

/*
 *  call-seq:
 *     Hash[ [key =>|, value]* ]   => hash
 *
 *  Creates a new hash populated with the given objects. Equivalent to
 *  the literal <code>{ <i>key</i>, <i>value</i>, ... }</code>. Keys and
 *  values occur in pairs, so there must be an even number of arguments.
 *
 *     Hash["a", 100, "b", 200]       #=> {"a"=>100, "b"=>200}
 *     Hash["a" => 100, "b" => 200]   #=> {"a"=>100, "b"=>200}
 *     { "a" => 100, "b" => 200 }     #=> {"a"=>100, "b"=>200}
 */

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

    if (argc == 1) {
    tmp = rb_check_convert_type(argv[0], T_HASH, "Hash", "to_hash");
    if (!NIL_P(tmp)) {
        hash = hash_alloc0(klass);
        RHASH(hash)->tbl = st_copy(RHASH(tmp)->tbl);
        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 v = rb_check_array_type(RARRAY_PTR(tmp)[i]);
        VALUE key, val = Qnil;

        if (NIL_P(v)) continue;
        switch (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;
}

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


# File 'hash.c'

/*
 *  call-seq:
 *     hsh == other_hash    => true or false
 *
 *  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
 *  <code>Object#==</code>) 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
 *
 */

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

#[](key) ⇒ Object

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

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


# File 'hash.c'

/*
 *  call-seq:
 *     hsh[key]    =>  value
 *
 *  Element Reference---Retrieves the <i>value</i> object corresponding
 *  to the <i>key</i> object. If not found, returns the a default value (see
 *  <code>Hash::new</code> for details).
 *
 *     h = { "a" => 100, "b" => 200 }
 *     h["a"]   #=> 100
 *     h["c"]   #=> nil
 *
 */

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

    if (!st_lookup(RHASH(hash)->tbl, key, &val)) {
    return rb_funcall(hash, id_default, 1, key);
    }
    return val;
}

#[]=(key) ⇒ Object #store(key, value) ⇒ Object

Element Assignment---Associates the value given by value with the key given by key. key should not have its value changed while it is in use as a key (a String passed as a key will be duplicated and frozen).

h = { "a" => 100, "b" => 200 }
h["a"] = 9
h["c"] = 4
h   #=> {"a"=>9, "b"=>200, "c"=>4}


# File 'hash.c'

/*
 *  call-seq:
 *     hsh[key] = value        => value
 *     hsh.store(key, value)   => value
 *
 *  Element Assignment---Associates the value given by
 *  <i>value</i> with the key given by <i>key</i>.
 *  <i>key</i> should not have its value changed while it is in
 *  use as a key (a <code>String</code> passed as a key will be
 *  duplicated and frozen).
 *
 *     h = { "a" => 100, "b" => 200 }
 *     h["a"] = 9
 *     h["c"] = 4
 *     h   #=> {"a"=>9, "b"=>200, "c"=>4}
 *
 */

VALUE
rb_hash_aset(hash, key, val)
    VALUE hash, key, val;
{
    rb_hash_modify(hash);
    if (TYPE(key) != T_STRING || st_lookup(RHASH(hash)->tbl, key, 0)) {
    st_insert(RHASH(hash)->tbl, key, val);
    }
    else {
    st_add_direct(RHASH(hash)->tbl, rb_str_new4(key), val);
    }
    return val;
}

#clearHash

Removes all key-value pairs from hsh.

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


# File 'hash.c'

/*
 *  call-seq:
 *     hsh.clear -> hsh
 *
 *  Removes all key-value pairs from <i>hsh</i>.
 *
 *     h = { "a" => 100, "b" => 200 }   #=> {"a"=>100, "b"=>200}
 *     h.clear                          #=> {}
 *
 */

static VALUE
rb_hash_clear(hash)
    VALUE hash;
{
    rb_hash_modify(hash);
    if (RHASH(hash)->tbl->num_entries > 0) {
    rb_hash_foreach(hash, clear_i, 0);
    }

    return hash;
}

#default(key = nil) ⇒ Object

Returns the default value, the value that would be returned by hsh 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


# File 'hash.c'

/*
 *  call-seq:
 *     hsh.default(key=nil)   => obj
 *
 *  Returns the default value, the value that would be returned by
 *  <i>hsh</i>[<i>key</i>] if <i>key</i> did not exist in <i>hsh</i>.
 *  See also <code>Hash::new</code> and <code>Hash#default=</code>.
 *
 *     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
 */

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

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

#default=(obj) ⇒ Hash

Sets the default value, the value returned for a key that does not exist in the hash. It is not possible to set the a 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>


# File 'hash.c'

/*
 *  call-seq:
 *     hsh.default = obj     => hsh
 *
 *  Sets the default value, the value returned for a key that does not
 *  exist in the hash. It is not possible to set the a default to a
 *  <code>Proc</code> 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>
 */

static VALUE
rb_hash_set_default(hash, ifnone)
    VALUE hash, ifnone;
{
    rb_hash_modify(hash);
    RHASH(hash)->ifnone = ifnone;
    FL_UNSET(hash, HASH_PROC_DEFAULT);
    return ifnone;
}

#default_procObject

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]


# File 'hash.c'

/*
 *  call-seq:
 *     hsh.default_proc -> anObject
 *
 *  If <code>Hash::new</code> was invoked with a block, return that
 *  block, otherwise return <code>nil</code>.
 *
 *     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]
 */


static VALUE
rb_hash_default_proc(hash)
    VALUE hash;
{
    if (FL_TEST(hash, HASH_PROC_DEFAULT)) {
    return RHASH(hash)->ifnone;
    }
    return Qnil;
}

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

Deletes and returns a key-value pair from hsh whose key is equal to key. If the key is not found, returns nil. 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:

    • (key)


# File 'hash.c'

/*
 *  call-seq:
 *     hsh.delete(key)                   => value
 *     hsh.delete(key) {| key | block }  => value
 *
 *  Deletes and returns a key-value pair from <i>hsh</i> whose key is
 *  equal to <i>key</i>. If the key is not found, returns <code>nil</code>.
 *  If the optional code block is given and the key is not found,
 *  pass in the key and return the result of <i>block</i>.
 *
 *     h = { "a" => 100, "b" => 200 }
 *     h.delete("a")                              #=> 100
 *     h.delete("z")                              #=> nil
 *     h.delete("z") { |el| "#{el} not found" }   #=> "z not found"
 *
 */

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

    rb_hash_modify(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

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

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

Yields:

  • (key, value)


# File 'hash.c'

/*
 *  call-seq:
 *     hsh.delete_if {| key, value | block }  -> hsh
 *
 *  Deletes every key-value pair from <i>hsh</i> for which <i>block</i>
 *  evaluates to <code>true</code>.
 *
 *     h = { "a" => 100, "b" => 200, "c" => 300 }
 *     h.delete_if {|key, value| key >= "b" }   #=> {"a"=>100}
 *
 */

VALUE
rb_hash_delete_if(hash)
    VALUE hash;
{
    RETURN_ENUMERATOR(hash, 0, 0);
    rb_hash_modify(hash);
    rb_hash_foreach(hash, delete_if_i, hash);
    return hash;
}

#each {|key, value| ... } ⇒ Hash

Calls block once for each key in hsh, passing the key and value to the block as a two-element array. Because of the assignment semantics of block parameters, these elements will be split out if the block has two formal parameters. Also see Hash.each_pair, which will be marginally more efficient for blocks with two parameters.

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

produces:

a is 100
b is 200

Yields:

  • (key, value)


# File 'hash.c'

/*
 *  call-seq:
 *     hsh.each {| key, value | block } -> hsh
 *
 *  Calls <i>block</i> once for each key in <i>hsh</i>, passing the key
 *  and value to the block as a two-element array. Because of the assignment
 *  semantics of block parameters, these elements will be split out if the
 *  block has two formal parameters. Also see <code>Hash.each_pair</code>, which
 *  will be marginally more efficient for blocks with two parameters.
 *
 *     h = { "a" => 100, "b" => 200 }
 *     h.each {|key, value| puts "#{key} is #{value}" }
 *
 *  <em>produces:</em>
 *
 *     a is 100
 *     b is 200
 *
 */

static VALUE
rb_hash_each(hash)
    VALUE hash;
{
    RETURN_ENUMERATOR(hash, 0, 0);
    rb_hash_foreach(hash, each_i, 0);
    return hash;
}

#each_key {|key| ... } ⇒ Hash

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

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

produces:

a
b

Yields:

  • (key)


# File 'hash.c'

/*
 *  call-seq:
 *     hsh.each_key {| key | block } -> hsh
 *
 *  Calls <i>block</i> once for each key in <i>hsh</i>, passing the key
 *  as a parameter.
 *
 *     h = { "a" => 100, "b" => 200 }
 *     h.each_key {|key| puts key }
 *
 *  <em>produces:</em>
 *
 *     a
 *     b
 */
static VALUE
rb_hash_each_key(hash)
    VALUE hash;
{
    RETURN_ENUMERATOR(hash, 0, 0);
    rb_hash_foreach(hash, each_key_i, 0);
    return hash;
}

#each_pair {|key_value_array| ... } ⇒ Hash

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

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

produces:

a is 100
b is 200

Yields:

  • (key_value_array)


# File 'hash.c'

/*
 *  call-seq:
 *     hsh.each_pair {| key_value_array | block } -> hsh
 *
 *  Calls <i>block</i> once for each key in <i>hsh</i>, passing the key
 *  and value as parameters.
 *
 *     h = { "a" => 100, "b" => 200 }
 *     h.each_pair {|key, value| puts "#{key} is #{value}" }
 *
 *  <em>produces:</em>
 *
 *     a is 100
 *     b is 200
 *
 */

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

#each_value {|value| ... } ⇒ Hash

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

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

produces:

100
200

Yields:

  • (value)


# File 'hash.c'

/*
 *  call-seq:
 *     hsh.each_value {| value | block } -> hsh
 *
 *  Calls <i>block</i> once for each key in <i>hsh</i>, passing the
 *  value as a parameter.
 *
 *     h = { "a" => 100, "b" => 200 }
 *     h.each_value {|value| puts value }
 *
 *  <em>produces:</em>
 *
 *     100
 *     200
 */

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

#empty?Boolean

Returns true if hsh contains no key-value pairs.

{}.empty?   #=> true


# File 'hash.c'

/*
 *  call-seq:
 *     hsh.empty?    => true or false
 *
 *  Returns <code>true</code> if <i>hsh</i> contains no key-value pairs.
 *
 *     {}.empty?   #=> true
 *
 */

static VALUE
rb_hash_empty_p(hash)
    VALUE hash;
{
    if (RHASH(hash)->tbl->num_entries == 0)
    return Qtrue;
    return Qfalse;
}

#eql?(other) ⇒ Boolean

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



# File 'hash.c'

/*
 *  call-seq:
 *     hash.eql?(other)  -> true or false
 *
 *  Returns <code>true</code> if <i>hash</i> and <i>other</i> are
 *  both hashes with the same content.
 */

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

#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 IndexError 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 (IndexError)
 from prog.rb:2

Overloads:

  • #fetch(key) {|key| ... } ⇒ Object

    Yields:

    • (key)


# File 'hash.c'

/*
 *  call-seq:
 *     hsh.fetch(key [, default] )       => obj
 *     hsh.fetch(key) {| key | block }   => obj
 *
 *  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 <code>IndexError</code> exception; if <i>default</i> 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")
 *
 *  <em>produces:</em>
 *
 *     prog.rb:2:in `fetch': key not found (IndexError)
 *      from prog.rb:2
 *
 */

static VALUE
rb_hash_fetch(argc, argv, hash)
    int argc;
    VALUE *argv;
    VALUE hash;
{
    VALUE key, if_none;
    VALUE 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 (!st_lookup(RHASH(hash)->tbl, key, &val)) {
    if (block_given) return rb_yield(key);
    if (argc == 1) {
        rb_raise(rb_eIndexError, "key not found");
    }
    return if_none;
    }
    return val;
}

#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


# File 'hash.c'

/*
 *  call-seq:
 *     hsh.has_key?(key)    => true or false
 *     hsh.include?(key)    => true or false
 *     hsh.key?(key)        => true or false
 *     hsh.member?(key)     => true or false
 *
 *  Returns <code>true</code> if the given key is present in <i>hsh</i>.
 *
 *     h = { "a" => 100, "b" => 200 }
 *     h.has_key?("a")   #=> true
 *     h.has_key?("z")   #=> false
 *
 */

static VALUE
rb_hash_has_key(hash, key)
    VALUE hash;
    VALUE key;
{
    if (st_lookup(RHASH(hash)->tbl, 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


# File 'hash.c'

/*
 *  call-seq:
 *     hsh.has_value?(value)    => true or false
 *     hsh.value?(value)        => true or false
 *
 *  Returns <code>true</code> if the given value is present for some key
 *  in <i>hsh</i>.
 *
 *     h = { "a" => 100, "b" => 200 }
 *     h.has_value?(100)   #=> true
 *     h.has_value?(999)   #=> false
 */

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

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

#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?).



# File 'hash.c'

/*
 *  call-seq:
 *     array.hash   -> fixnum
 *
 *  Compute a hash-code for this array. Two arrays with the same content
 *  will have the same hash code (and will compare using <code>eql?</code>).
 */

static VALUE
rb_hash_hash(hash)
    VALUE hash;
{
    return rb_exec_recursive(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


# File 'hash.c'

/*
 *  call-seq:
 *     hsh.has_key?(key)    => true or false
 *     hsh.include?(key)    => true or false
 *     hsh.key?(key)        => true or false
 *     hsh.member?(key)     => true or false
 *
 *  Returns <code>true</code> if the given key is present in <i>hsh</i>.
 *
 *     h = { "a" => 100, "b" => 200 }
 *     h.has_key?("a")   #=> true
 *     h.has_key?("z")   #=> false
 *
 */

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

#index(value) ⇒ Object

Returns the key for a given value. If not found, returns nil.

h = { "a" => 100, "b" => 200 }
h.index(200)   #=> "b"
h.index(999)   #=> nil


# File 'hash.c'

/*
 *  call-seq:
 *     hsh.index(value)    => key
 *
 *  Returns the key for a given value. If not found, returns <code>nil</code>.
 *
 *     h = { "a" => 100, "b" => 200 }
 *     h.index(200)   #=> "b"
 *     h.index(999)   #=> nil
 *
 */

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

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

    rb_hash_foreach(hash, index_i, (st_data_t)args);

    return args[1];
}

#indexes(key, ...) ⇒ Array #indices(key, ...) ⇒ Array

Deprecated in favor of Hash#select.



# File 'hash.c'

/*
 *  call-seq:
 *     hsh.indexes(key, ...)    => array
 *     hsh.indices(key, ...)    => array
 *
 *  Deprecated in favor of <code>Hash#select</code>.
 *
 */

static VALUE
rb_hash_indexes(argc, argv, hash)
    int argc;
    VALUE *argv;
    VALUE hash;
{
    VALUE indexes;
    int i;

    rb_warn("Hash#%s is deprecated; use Hash#values_at",
        rb_id2name(rb_frame_last_func()));
    indexes = rb_ary_new2(argc);
    for (i=0; i<argc; i++) {
    RARRAY(indexes)->ptr[i] = rb_hash_aref(hash, argv[i]);
    RARRAY(indexes)->len++;
    }
    return indexes;
}

#indexes(key, ...) ⇒ Array #indices(key, ...) ⇒ Array

Deprecated in favor of Hash#select.



# File 'hash.c'

/*
 *  call-seq:
 *     hsh.indexes(key, ...)    => array
 *     hsh.indices(key, ...)    => array
 *
 *  Deprecated in favor of <code>Hash#select</code>.
 *
 */

static VALUE
rb_hash_indexes(argc, argv, hash)
    int argc;
    VALUE *argv;
    VALUE hash;
{
    VALUE indexes;
    int i;

    rb_warn("Hash#%s is deprecated; use Hash#values_at",
        rb_id2name(rb_frame_last_func()));
    indexes = rb_ary_new2(argc);
    for (i=0; i<argc; i++) {
    RARRAY(indexes)->ptr[i] = rb_hash_aref(hash, argv[i]);
    RARRAY(indexes)->len++;
    }
    return indexes;
}

#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}


# File 'hash.c'

/*
 *  call-seq:
 *     hsh.replace(other_hash) -> hsh
 *
 *  Replaces the contents of <i>hsh</i> with the contents of
 *  <i>other_hash</i>.
 *
 *     h = { "a" => 100, "b" => 200 }
 *     h.replace({ "c" => 300, "d" => 400 })   #=> {"c"=>300, "d"=>400}
 *
 */

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

    return hash;
}

#inspectString

Return the contents of this hash as a string.



# File 'hash.c'

/*
 * call-seq:
 *   hsh.inspect  => string
 *
 * Return the contents of this hash as a string.
 */

static VALUE
rb_hash_inspect(hash)
    VALUE hash;
{
    if (RHASH(hash)->tbl == 0 || RHASH(hash)->tbl->num_entries == 0)
    return rb_str_new2("{}");
    if (rb_inspecting_p(hash)) return rb_str_new2("{...}");
    return rb_protect_inspect(inspect_hash, hash, 0);
}

#invertHash

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=>"n", 200=>"d", 300=>"y"}


# File 'hash.c'

/*
 *  call-seq:
 *     hsh.invert -> aHash
 *
 *  Returns a new hash created by using <i>hsh</i>'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=>"n", 200=>"d", 300=>"y"}
 *
 */

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

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

#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


# File 'hash.c'

/*
 *  call-seq:
 *     hsh.has_key?(key)    => true or false
 *     hsh.include?(key)    => true or false
 *     hsh.key?(key)        => true or false
 *     hsh.member?(key)     => true or false
 *
 *  Returns <code>true</code> if the given key is present in <i>hsh</i>.
 *
 *     h = { "a" => 100, "b" => 200 }
 *     h.has_key?("a")   #=> true
 *     h.has_key?("z")   #=> false
 *
 */

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

#keysArray

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"]


# File 'hash.c'

/*
 *  call-seq:
 *     hsh.keys    => array
 *
 *  Returns a new array populated with the keys from this hash. See also
 *  <code>Hash#values</code>.
 *
 *     h = { "a" => 100, "b" => 200, "c" => 300, "d" => 400 }
 *     h.keys   #=> ["a", "b", "c", "d"]
 *
 */

static VALUE
rb_hash_keys(hash)
    VALUE hash;
{
    VALUE ary;

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

    return ary;
}

#lengthFixnum #sizeFixnum

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


# File 'hash.c'

/*
 *  call-seq:
 *     hsh.length    =>  fixnum
 *     hsh.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
 */

static VALUE
rb_hash_size(hash)
    VALUE hash;
{
    return INT2FIX(RHASH(hash)->tbl->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


# File 'hash.c'

/*
 *  call-seq:
 *     hsh.has_key?(key)    => true or false
 *     hsh.include?(key)    => true or false
 *     hsh.key?(key)        => true or false
 *     hsh.member?(key)     => true or false
 *
 *  Returns <code>true</code> if the given key is present in <i>hsh</i>.
 *
 *     h = { "a" => 100, "b" => 200 }
 *     h.has_key?("a")   #=> true
 *     h.has_key?("z")   #=> false
 *
 */

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

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

Returns a new hash containing the contents of other_hash and the contents of hsh, overwriting entries in hsh with duplicate keys with those from 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}

Overloads:

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

    Yields:

    • (key, oldval, newval)


# File 'hash.c'

/*
 *  call-seq:
 *     hsh.merge(other_hash)                              -> a_hash
 *     hsh.merge(other_hash){|key, oldval, newval| block} -> a_hash
 *
 *  Returns a new hash containing the contents of <i>other_hash</i> and
 *  the contents of <i>hsh</i>, overwriting entries in <i>hsh</i> with
 *  duplicate keys with those from <i>other_hash</i>.
 *
 *     h1 = { "a" => 100, "b" => 200 }
 *     h2 = { "b" => 254, "c" => 300 }
 *     h1.merge(h2)   #=> {"a"=>100, "b"=>254, "c"=>300}
 *     h1             #=> {"a"=>100, "b"=>200}
 *
 */

static VALUE
rb_hash_merge(hash1, hash2)
    VALUE hash1, 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) {|key, oldval, newval| ... } ⇒ Hash

    Yields:

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

    Yields:

    • (key, oldval, newval)


# File 'hash.c'

/*
 *  call-seq:
 *     hsh.merge!(other_hash)                                 => hsh
 *     hsh.update(other_hash)                                 => hsh
 *     hsh.merge!(other_hash){|key, oldval, newval| block}    => hsh
 *     hsh.update(other_hash){|key, oldval, newval| block}    => hsh
 *
 *  Adds the contents of <i>other_hash</i> to <i>hsh</i>.  If no
 *  block is specified entries with duplicate keys are overwritten
 *  with the values from <i>other_hash</i>, otherwise the value
 *  of each duplicate key is determined by calling the block with
 *  the key, its value in <i>hsh</i> and its value in <i>other_hash</i>.
 *
 *     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}
 */

static VALUE
rb_hash_update(hash1, hash2)
    VALUE hash1, hash2;
{
    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;
}

#rehashHash

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 IndexError 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


# File 'hash.c'

/*
 *  call-seq:
 *     hsh.rehash -> hsh
 *
 *  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 <i>hsh</i>. If <code>Hash#rehash</code> is
 *  called while an iterator is traversing the hash, an
 *  <code>IndexError</code> 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
 */

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

    rb_hash_modify(hash);
    tbl = st_init_table_with_size(&objhash, RHASH(hash)->tbl->num_entries);
    rb_hash_foreach(hash, rb_hash_rehash_i, (st_data_t)tbl);
    st_free_table(RHASH(hash)->tbl);
    RHASH(hash)->tbl = tbl;

    return hash;
}

#reject {|key, value| ... } ⇒ Hash

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

Yields:

  • (key, value)


# File 'hash.c'

/*
 *  call-seq:
 *     hsh.reject {| key, value | block }  -> a_hash
 *
 *  Same as <code>Hash#delete_if</code>, but works on (and returns) a
 *  copy of the <i>hsh</i>. Equivalent to
 *  <code><i>hsh</i>.dup.delete_if</code>.
 *
 */

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

#reject! {|key, value| ... } ⇒ Hash?

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

Yields:

  • (key, value)


# File 'hash.c'

/*
 *  call-seq:
 *     hsh.reject! {| key, value | block }  -> hsh or nil
 *
 *  Equivalent to <code>Hash#delete_if</code>, but returns
 *  <code>nil</code> if no changes were made.
 */

VALUE
rb_hash_reject_bang(hash)
    VALUE hash;
{
    int n;

    RETURN_ENUMERATOR(hash, 0, 0);
    n = RHASH(hash)->tbl->num_entries;
    rb_hash_delete_if(hash);
    if (n == RHASH(hash)->tbl->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}


# File 'hash.c'

/*
 *  call-seq:
 *     hsh.replace(other_hash) -> hsh
 *
 *  Replaces the contents of <i>hsh</i> with the contents of
 *  <i>other_hash</i>.
 *
 *     h = { "a" => 100, "b" => 200 }
 *     h.replace({ "c" => 300, "d" => 400 })   #=> {"c"=>300, "d"=>400}
 *
 */

static VALUE
rb_hash_replace(hash, hash2)
    VALUE hash, hash2;
{
    hash2 = to_hash(hash2);
    if (hash == hash2) return hash;
    rb_hash_clear(hash);
    rb_hash_foreach(hash2, replace_i, hash);
    RHASH(hash)->ifnone = RHASH(hash2)->ifnone;
    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| ... } ⇒ Array

Returns a new array consisting of [key,value] pairs for which the block returns true. Also see Hash.values_at.

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]]

Yields:

  • (key, value)


# File 'hash.c'

/*
 *  call-seq:
 *     hsh.select {|key, value| block}   => array
 *
 *  Returns a new array consisting of <code>[key,value]</code>
 *  pairs for which the block returns true.
 *  Also see <code>Hash.values_at</code>.
 *
 *     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]]
 */

VALUE
rb_hash_select(hash)
    VALUE hash;
{
    VALUE result;

    RETURN_ENUMERATOR(hash, 0, 0);
    result = rb_ary_new();
    rb_hash_foreach(hash, select_i, result);
    return result;
}

#shiftArray, 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"}


# File 'hash.c'

/*
 *  call-seq:
 *     hsh.shift -> anArray or obj
 *
 *  Removes a key-value pair from <i>hsh</i> and returns it as the
 *  two-item array <code>[</code> <i>key, value</i> <code>]</code>, 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"}
 */

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

    rb_hash_modify(hash);
    var.key = Qundef;
    if (RHASH(hash)->iter_lev > 0) {
    rb_hash_foreach(hash, shift_i_safe, (st_data_t)&var);
    if (var.key != Qundef) {
        st_data_t key = var.key;
        if (st_delete_safe(RHASH(hash)->tbl, &key, 0, Qundef)) {
        FL_SET(hash, HASH_DELETED);
        }
    }
    }
    else {
    rb_hash_foreach(hash, shift_i, (st_data_t)&var);
    }

    if (var.key != Qundef) {
    return rb_assoc_new(var.key, var.val);
    }
    else if (FL_TEST(hash, HASH_PROC_DEFAULT)) {
    return rb_funcall(RHASH(hash)->ifnone, id_call, 2, hash, Qnil);
    }
    else {
    return RHASH(hash)->ifnone;
    }
}

#lengthFixnum #sizeFixnum

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


# File 'hash.c'

/*
 *  call-seq:
 *     hsh.length    =>  fixnum
 *     hsh.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
 */

static VALUE
rb_hash_size(hash)
    VALUE hash;
{
    return INT2FIX(RHASH(hash)->tbl->num_entries);
}

#sortArray #sort {|a, b| ... } ⇒ Array

Converts hsh to a nested array of [ key, value ] arrays and sorts it, using Array#sort.

h = { "a" => 20, "b" => 30, "c" => 10  }
h.sort                       #=> [["a", 20], ["b", 30], ["c", 10]]
h.sort {|a,b| a[1]<=>b[1]}   #=> [["c", 10], ["a", 20], ["b", 30]]

Overloads:

  • #sort {|a, b| ... } ⇒ Array

    Yields:

    • (a, b)


# File 'hash.c'

/*
 *  call-seq:
 *     hsh.sort                    => array
 *     hsh.sort {| a, b | block }  => array
 *
 *  Converts <i>hsh</i> to a nested array of <code>[</code> <i>key,
 *  value</i> <code>]</code> arrays and sorts it, using
 *  <code>Array#sort</code>.
 *
 *     h = { "a" => 20, "b" => 30, "c" => 10  }
 *     h.sort                       #=> [["a", 20], ["b", 30], ["c", 10]]
 *     h.sort {|a,b| a[1]<=>b[1]}   #=> [["c", 10], ["a", 20], ["b", 30]]
 *
 */

static VALUE
rb_hash_sort(hash)
    VALUE hash;
{
    VALUE entries = rb_hash_to_a(hash);
    rb_ary_sort_bang(entries);
    return entries;
}

#[]=(key) ⇒ Object #store(key, value) ⇒ Object

Element Assignment---Associates the value given by value with the key given by key. key should not have its value changed while it is in use as a key (a String passed as a key will be duplicated and frozen).

h = { "a" => 100, "b" => 200 }
h["a"] = 9
h["c"] = 4
h   #=> {"a"=>9, "b"=>200, "c"=>4}


# File 'hash.c'

/*
 *  call-seq:
 *     hsh[key] = value        => value
 *     hsh.store(key, value)   => value
 *
 *  Element Assignment---Associates the value given by
 *  <i>value</i> with the key given by <i>key</i>.
 *  <i>key</i> should not have its value changed while it is in
 *  use as a key (a <code>String</code> passed as a key will be
 *  duplicated and frozen).
 *
 *     h = { "a" => 100, "b" => 200 }
 *     h["a"] = 9
 *     h["c"] = 4
 *     h   #=> {"a"=>9, "b"=>200, "c"=>4}
 *
 */

VALUE
rb_hash_aset(hash, key, val)
    VALUE hash, key, val;
{
    rb_hash_modify(hash);
    if (TYPE(key) != T_STRING || st_lookup(RHASH(hash)->tbl, key, 0)) {
    st_insert(RHASH(hash)->tbl, key, val);
    }
    else {
    st_add_direct(RHASH(hash)->tbl, rb_str_new4(key), val);
    }
    return val;
}

#to_aArray

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

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


# File 'hash.c'

/*
 *  call-seq:
 *     hsh.to_a -> array
 *
 *  Converts <i>hsh</i> to a nested array of <code>[</code> <i>key,
 *  value</i> <code>]</code> arrays.
 *
 *     h = { "c" => 300, "a" => 100, "d" => 400, "c" => 300  }
 *     h.to_a   #=> [["a", 100], ["c", 300], ["d", 400]]
 */

static VALUE
rb_hash_to_a(hash)
    VALUE hash;
{
    VALUE ary;

    ary = rb_ary_new();
    rb_hash_foreach(hash, to_a_i, ary);
    if (OBJ_TAINTED(hash)) OBJ_TAINT(ary);

    return ary;
}

#to_hashHash

Returns self.



# File 'hash.c'

/*
 * call-seq:
 *    hsh.to_hash   => hsh
 *
 * Returns <i>self</i>.
 */

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

#to_sString

Converts hsh to a string by converting the hash to an array of [ key, value ] pairs and then converting that array to a string using Array#join with the default separator.

h = { "c" => 300, "a" => 100, "d" => 400, "c" => 300  }
h.to_s   #=> "a100c300d400"


# File 'hash.c'

/*
 *  call-seq:
 *     hsh.to_s   => string
 *
 *  Converts <i>hsh</i> to a string by converting the hash to an array
 *  of <code>[</code> <i>key, value</i> <code>]</code> pairs and then
 *  converting that array to a string using <code>Array#join</code> with
 *  the default separator.
 *
 *     h = { "c" => 300, "a" => 100, "d" => 400, "c" => 300  }
 *     h.to_s   #=> "a100c300d400"
 */

static VALUE
rb_hash_to_s(hash)
    VALUE hash;
{
    if (rb_inspecting_p(hash)) return rb_str_new2("{...}");
    return rb_protect_inspect(to_s_hash, hash, 0);
}

#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) {|key, oldval, newval| ... } ⇒ Hash

    Yields:

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

    Yields:

    • (key, oldval, newval)


# File 'hash.c'

/*
 *  call-seq:
 *     hsh.merge!(other_hash)                                 => hsh
 *     hsh.update(other_hash)                                 => hsh
 *     hsh.merge!(other_hash){|key, oldval, newval| block}    => hsh
 *     hsh.update(other_hash){|key, oldval, newval| block}    => hsh
 *
 *  Adds the contents of <i>other_hash</i> to <i>hsh</i>.  If no
 *  block is specified entries with duplicate keys are overwritten
 *  with the values from <i>other_hash</i>, otherwise the value
 *  of each duplicate key is determined by calling the block with
 *  the key, its value in <i>hsh</i> and its value in <i>other_hash</i>.
 *
 *     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}
 */

static VALUE
rb_hash_update(hash1, hash2)
    VALUE hash1, hash2;
{
    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


# File 'hash.c'

/*
 *  call-seq:
 *     hsh.has_value?(value)    => true or false
 *     hsh.value?(value)        => true or false
 *
 *  Returns <code>true</code> if the given value is present for some key
 *  in <i>hsh</i>.
 *
 *     h = { "a" => 100, "b" => 200 }
 *     h.has_value?(100)   #=> true
 *     h.has_value?(999)   #=> false
 */

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

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

#valuesArray

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]


# File 'hash.c'

/*
 *  call-seq:
 *     hsh.values    => array
 *
 *  Returns a new array populated with the values from <i>hsh</i>. See
 *  also <code>Hash#keys</code>.
 *
 *     h = { "a" => 100, "b" => 200, "c" => 300 }
 *     h.values   #=> [100, 200, 300]
 *
 */

static VALUE
rb_hash_values(hash)
    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"]


# File 'hash.c'

/*
 * call-seq:
 *   hsh.values_at(key, ...)   => array
 *
 * Return an array containing the values associated with the given keys.
 * Also see <code>Hash.select</code>.
 *
 *   h = { "cat" => "feline", "dog" => "canine", "cow" => "bovine" }
 *   h.values_at("cow", "cat")  #=> ["bovine", "feline"]
 */

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

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