method

first

v1_8_7_330 - Show latest stable - 1 note - Class: Enumerable

first(...) public

Returns the first element, or the first n elements, of the enumerable. If the enumerable is empty, the first form returns nil, and the second form returns an empty array.

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/*
 *  call-seq:
 *     enum.first      -> obj or nil
 *     enum.first(n)   -> an_array
 *
 *  Returns the first element, or the first +n+ elements, of the enumerable.
 *  If the enumerable is empty, the first form returns <code>nil</code>, and the
 *  second form returns an empty array.
 *
 */

static VALUE
enum_first(argc, argv, obj)
    int argc;
    VALUE *argv;
    VALUE obj;
{
    VALUE n, ary[2];

    if (argc == 0) {
        ary[0] = ary[1] = Qnil;
    }
    else {
        long len;
        rb_scan_args(argc, argv, "01", &n);
        len = NUM2LONG(n);
        if (len == 0) return rb_ary_new2(0);
        ary[0] = INT2NUM(len);
        ary[1] = rb_ary_new2(len);
    }
    rb_block_call(obj, id_each, 0, 0, first_i, (VALUE)ary);

    return ary[1];
}

March 15, 2012

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Video Explanation of first, last and each

http://www.youtube.com/watch?feature=player_embedded&v=rQIJ0WJXOr8

first

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Video Explanation of first, last and each