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array_keys

(PHP 4, PHP 5, PHP 7, PHP 8)

array_keys — Return all the keys or a subset of the keys of an array

Опис

array_keys(array $array): array
array_keys(array $array, mixed $filter_value, bool $strict = false): array

array_keys() returns the keys, numeric and string, from the array.

If a filter_value is specified, then only the keys for that value are returned. Otherwise, all the keys from the array are returned.

Параметри

array

An array containing keys to return.

filter_value

If specified, then only keys containing this value are returned.

strict

Determines if strict comparison (===) should be used during the search.

Значення, що повертаються

Returns an array of all the keys in array.

Приклади

Приклад #1 array_keys() example

<?php
$array = array(0 => 100, "color" => "red");
print_r(array_keys($array));

$array = array("blue", "red", "green", "blue", "blue");
print_r(array_keys($array, "blue"));

$array = array("color" => array("blue", "red", "green"),
"size" => array("small", "medium", "large"));
print_r(array_keys($array));
?>

Поданий вище приклад виведе:

Array
(
    [0] => 0
    [1] => color
)
Array
(
    [0] => 0
    [1] => 3
    [2] => 4
)
Array
(
    [0] => color
    [1] => size
)

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