Ruby » Ruby master

Mon Mar 27 01:20:05 2012 Sambasiva Rao Suda <sambasivarao@gmail.org>

* hash.c (rb_hash_keys_of): Adding new method Hash#keys_of(value),

which will return array having all the keys of the given value.

[ruby-dev:45310][Feature #6118]

static int

keys_of_i(VALUE key, VALUE value, VALUE ary)

{

VALUE arg = rb_ary_entry(ary, 0);

if (rb_equal(value, arg)) {

rb_ary_push(ary, key);

}

return ST_CONTINUE;

}

/*

* call-seq:

* hsh.keys_of(value) -> [key]

*

* Returns the keys of a given value. If the value is

* not found, returns <code>[]</code>.

*

* h = { "a" => 100, "b" => 200, "c" => 300, "d" => 300}

* h.key(200) #=> ["b"]

* h.key(300) #=> ["c", "d"]

* h.key(999) #=> []

*

*/

static VALUE

rb_hash_keys_of(VALUE hash, VALUE value)

{

VALUE ary;

ary = rb_ary_new();

rb_ary_push(ary, value);

rb_hash_foreach(hash, keys_of_i, ary);

rb_ary_shift(ary);

return ary;

}

1 => 'one', 2 => 'two', 3 => 'three', 4 => 'two',

def test_keys_of

assert_equal([1], @h.keys_of('one'))

assert_equal([2, 4], @h.keys_of('two'))

assert_equal([], @h.keys_of('nil'))

assert_equal([], @h.keys_of('gumby'))

assert_equal([], @cls[].keys_of('gumby'))

end