array_find_key

(PHP 8 >= 8.4.0)

array_find_key — Returns the key of the first element satisfying a callback function

Опис

array_find_key(array $array, callable $callback): mixed

array_find_key() returns the key of the first element of an array for which the given callback returns true. If no matching element is found the function returns null.

Параметри

array

The array that should be searched.

callback

The callback function to call to check each element, which must be

callback(mixed $value, mixed $key): bool

If this function returns true, the key is returned from array_find_key() and the callback will not be called for further elements.

Значення, що повертаються

The function returns the key of the first element for which the callback returns true. If no matching element is found the function returns null.

Приклади

Приклад #1 array_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 $value) {
    return strlen($value) > 4;
}));

// Find the first animal whose name begins with f.
var_dump(array_find_key($array, function (string $value) {
    return str_starts_with($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, $key) {
   return preg_match('/^([a-f])$/', $key);
}));
?>

Поданий вище приклад виведе:

string(1) "e"
NULL
string(1) "c"
string(1) "a"

Прогляньте також

array_find() - Returns the first element satisfying a callback function
array_all() - Checks if all array elements satisfy a callback function
array_any() - Checks if at least one array element satisfies a callback function
array_filter() - Filters elements of an array using a callback function
array_reduce() - Iteratively reduce the array to a single value using a callback function