rassoc(p1)
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
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]; }