Method: Array#uniq

Defined in:

array.c

#uniq ⇒ Object #uniq {|element| ... } ⇒ Object

Returns a new array containing those elements from self that are not duplicates, the first occurrence always being retained.

With no block given, identifies and omits duplicate elements using method eql? to compare elements:

a = [0, 0, 1, 1, 2, 2]
a.uniq # => [0, 1, 2]

With a block given, calls the block for each element; identifies and omits “duplicate” elements using method eql? to compare block return values; that is, an element is a duplicate if its block return value is the same as that of a previous element:

a = ['a', 'aa', 'aaa', 'b', 'bb', 'bbb']
a.uniq {|element| element.size } # => ["a", "aa", "aaa"]

Related: Methods for Fetching.

Overloads:

• #uniq {|element| ... } ⇒ Object

  Yields:

  • (element)

# File 'array.c', line 6359

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

    if (RARRAY_LEN(ary) <= 1) {
        hash = 0;
        uniq = rb_ary_dup(ary);
    }
    else if (rb_block_given_p()) {
        hash = ary_make_hash_by(ary);
        uniq = rb_hash_values(hash);
    }
    else {
        hash = ary_make_hash(ary);
        uniq = rb_hash_values(hash);
    }

    return uniq;
}