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instance method

Range#first

first → object

first(n) → array

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

    if (NIL_P(RANGE_BEG(range))) {
        rb_raise(rb_eRangeError, "cannot get the first element of beginless range");
    }
    if (argc == 0) return RANGE_BEG(range);

    rb_scan_args(argc, argv, "1", &n);
    ary[0] = n;
    ary[1] = rb_ary_new2(NUM2LONG(n));
    rb_block_call(range, idEach, 0, 0, first_i, (VALUE)ary);

    return ary[1];
}

With no argument, returns the first element of self, if it exists:

Example

(1..4).first     # => 1
('a'..'d').first # => "a"

With non-negative integer argument n given, returns the first n elements in an array:

Example

(1..10).first(3) # => [1, 2, 3]
(1..10).first(0) # => []
(1..4).first(50) # => [1, 2, 3, 4]

Raises an exception if there is no first element:

Example

(..4).first # Raises RangeError

See also #exclude_end? #hash #eql? #include? also in 4.1 · 4.0 · 3.4 · 3.3 · 3.2 · 3.0

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