(PHP 7 >= 7.3.0, PHP 8)

array_key_firstGets 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.

Elenco dei parametri


An array.

Valori restituiti

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


Example #1 Basic array_key_first() Usage

= ['a' => 1'b' => 2'c' => 3];

$firstKey array_key_first($array);


Il precedente esempio visualizzerĂ :

string(1) "a"



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:

if (!function_exists('array_key_first')) {
array_key_first(array $arr) {
$arr as $key => $unused) {

Vedere anche:

  • array_key_last() - Gets the last key of an array
  • reset() - Reimposta il puntatore interno di un array sulla posizione iniziale
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