(PHP 8 >= 8.4.0)
array_find_key —Returns the key of the first element satisfying a callback function
array_find_key() returns the key of the first element of anarray for which the givencallback returnstrue. If no matching element is found the function returnsnull.
The function returns the key of the first element for which thecallback returnstrue. If no matching element is found the function returnsnull.
Example #1array_find_key() example
<?php
$array= [
'a'=>'dog',
'b'=>'cat',
'c'=>'cow',
'd'=>'duck',
'e'=>'goose',
'f'=>'elephant'
];
// Find the first animal with a name longer than 4 characters.
var_dump(array_find_key($array, function (string $value) {
returnstrlen($value) >4;
}));
// Find the first animal whose name begins with f.
var_dump(array_find_key($array, function (string $value) {
returnstr_starts_with($value,'f');
}));
// Find the first animal where the array key is the first symbol of the animal.
var_dump(array_find_key($array, function (string $value,$key) {
return$value[0] ===$key;
}));
// Find the first animal where the array key matching a RegEx.
var_dump(array_find_key($array, function ($value,$key) {
returnpreg_match('/^([a-f])$/',$key);
}));
?>The above example will output:
string(1) "e"NULLstring(1) "c"string(1) "a"