method

pop

v1_8_7_72 - Show latest stable - 2 notes - Class: Array

pop(...) public

Removes the last element from self and returns it, or nil if the array is empty.

If a number n is given, returns an array of the last n elements (or less) just like array.slice!(-n, n) does.

   a = [ "a", "b", "c", "d" ]
   a.pop     #=> "d"
   a.pop(2)  #=> ["b", "c"]
   a         #=> ["a"]

Show source

/*
 *  call-seq:
 *     array.pop    -> obj or nil
 *     array.pop(n) -> array
 *  
 *  Removes the last element from <i>self</i> and returns it, or
 *  <code>nil</code> if the array is empty.
 *
 *  If a number _n_ is given, returns an array of the last n elements
 *  (or less) just like <code>array.slice!(-n, n)</code> does.
 *     
 *     a = [ "a", "b", "c", "d" ]
 *     a.pop     #=> "d"
 *     a.pop(2)  #=> ["b", "c"]
 *     a         #=> ["a"]
 */

static VALUE
rb_ary_pop_m(argc, argv, ary)
    int argc;
    VALUE *argv;
    VALUE ary;
{
    VALUE result;

    if (argc == 0) {
        return rb_ary_pop(ary);
    }

    rb_ary_modify_check(ary);
    result = ary_shared_first(argc, argv, ary, Qtrue);
    RARRAY(ary)->len -= RARRAY(result)->len;
    return result;
}

November 18, 2008

9 thanks

Pop for last, Shift for first

If you want to pop the first element instead of the last one, use shift .

October 5, 2009

1 thank

Using argument version in ruby < 1.8.7

The argument to this method was added in Ruby 1.8.7. If you want to use this form in an earlier version, you must instead use the slice! method.

It is mentioned up in the docs, but here it is again for reference:

# Ruby >= 1.8.7
p = list.pop(n)

# Ruby < 1.8.7
p = list.slice!(-n, n)

pop

Related methods

Pop for last, Shift for first

Using argument version in ruby < 1.8.7