(PHP 4, PHP 5)
array_keys — Return all the keys or a subset of the keys of an array
array_keys() returns the keys, numeric and string, from the input array.
If the optional search_value is specified, then only the keys for that value are returned. Otherwise, all the keys from the input are returned.
An array containing keys to return.
If specified, then only keys containing these values are returned.
Determines if strict comparison (===) should be used during the search.
Returns an array of all the keys in input.
| Version | Description |
|---|---|
| 5.0.0 | Added the strict parameter. |
Example #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));
?>
The above example will output:
Array
(
[0] => 0
[1] => color
)
Array
(
[0] => 0
[1] => 3
[2] => 4
)
Array
(
[0] => color
[1] => size
)