method

first

v1_8_7_330 - Show latest stable - 2 notes - Class: Array

first(...) public

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

a = [ "q", "r", "s", "t" ]
a.first    #=> "q"
a.first(1) #=> ["q"]
a.first(3) #=> ["q", "r", "s"]

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/*
 *  call-seq:
 *     array.first   ->   obj or nil
 *     array.first(n) -> an_array
 *
 *  Returns the first element, or the first +n+ elements, of the array.
 *  If the array is empty, the first form returns <code>nil</code>, and the
 *  second form returns an empty array.
 *
 *     a = [ "q", "r", "s", "t" ]
 *     a.first    #=> "q"
 *     a.first(1) #=> ["q"]
 *     a.first(3) #=> ["q", "r", "s"]
 */

static VALUE
rb_ary_first(argc, argv, ary)
    int argc;
    VALUE *argv;
    VALUE ary;
{
    if (argc == 0) {
        if (RARRAY(ary)->len == 0) return Qnil;
        return RARRAY(ary)->ptr[0];
    }
    else {
        return ary_shared_first(argc, argv, ary, Qfalse);
    }
}

April 16, 2009

1 thank

Extracting the First Element

To extract the first element from an Array, use shift:

array = [ 1, 2, 3 ]           # => [ 1, 2, 3 ]
array.first                   # => 1
array                         # => [ 1, 2, 3 ]
array.shift                   # => 1
array                         # => [ 2, 3 ]

March 15, 2012

0 thanks

Video Explanation of first, last and each

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

first

Related methods

Extracting the First Element

Video Explanation of first, last and each