array_key_first

PHP 7 >= 7.3.0, PHP 8
array_key_first - Gets the first key of an array

array_key_first( array$array ): int|string|null

Get the first key of the given array without affecting the internal array pointer.

Parameters

array

An array.

Return Values

Returns the first key of array if the array is not empty; null otherwise.

Notes

There are several ways to provide this functionality for versions prior to PHP 7.3.0. It is possible to use array_keys, but that may be rather inefficient. It is also possible to use reset and key, but that may change the internal array pointer. An efficient solution, which does not change the internal array pointer, written as polyfill:

<?php
if (!function_exists('array_key_first')) {
    function 
array_key_first(array $arr) {
        foreach(
$arr as $key => $unused) {
            return 
$key;
        }
        return 
NULL;
    }
}
?>

Related Functions

Example of array_key_first

Show all examples for array_key_first

PHP Version: