(PHP 7 >= 7.3.0)
array_key_last — Gets the last key of an array
Get the last key of the given array without affecting
the internal array pointer.
arrayAn array.
Returns the last key of array if the array is not empty;
NULL otherwise.
Try to beat this polyfill in terms of performance!
<?php
if( !function_exists('array_key_last') ) {
function array_key_last(array $array) {
if( !empty($array) ) return key(array_slice($array, -1, 1, true));
}
}
// Bonus
if (!function_exists('array_key_first')) {
function array_key_first(array $arr) {
foreach($arr as $key => $unused) return $key;
}
}
?>
<?php
// PHP >= 7
function _array_key_last(array $array){
return (!empty($array)) ? array_keys($array)[count($array)-1] : null;
}
var_dump(_array_key_last(['PHP', 'Javascript', 'Python'])); // 2
?>
For those who loves tested candies;
<?php
function array_key_last(array $array) {
// 100000 iters: ~0.068 secs
return key(array_slice($array, -1));
// 100000 iters: ~0.070 secs
return key(array_reverse($array));
// 100000 iters: ~0.088 secs
return array_keys($array)[count($array) - 1] ?? null;
}
?>
This polyfill works for PHP 5.6+.
It is a slight modification of "wes at nospam dot example dot org"'s example:
<?php
if( !function_exists('array_key_first') ) {
function array_key_first(array $array) {
if( $array === [] ) { return NULL; }
foreach($array as $key => $_) { return $key; }
}
}
if( !function_exists('array_key_last') ) {
function array_key_last(array $array) {
if( $array === [] ) { return null; }
// the last 2 args to array_slice are crucial
return array_key_first(array_slice($array, -1, null, true));
}
}
Correct polyfill (one that doesn't make copies of arrays, and that doesn't make use of the IAP) is:
<?php
if(!function_exists('array_key_first')){
function array_key_first(array $array){
if($array === []){
return NULL;
}
foreach($array as $key => $_) return $key;
}
}
if(!function_exists('array_key_last')){
function array_key_last(array $array){
if($array === []){
return NULL;
}
return array_key_first(array_slice($array, -1));
}
}
?>
For PHP < 7.3.0 :
Will work for any type of array
<?php
if ( ! function_exists( 'array_key_last' ) ) {
/**
* Polyfill for array_key_last() function added in PHP 7.3.
*
* Get the last key of the given array without affecting
* the internal array pointer.
*
* @param array $array An array
*
* @return mixed The last key of array if the array is not empty; NULL otherwise.
*/
function array_key_last( $array ) {
$key = NULL;
if ( is_array( $array ) ) {
end( $array );
$key = key( $array );
}
return $key;
}
}
?>
For PHP <= 7.3.0 :
if (! function_exists("array_key_last")) {
function array_key_last($array) {
if (!is_array($array) || empty($array)) {
return NULL;
}
return array_keys($array)[count($array)-1];
}
}