array_keys
(PHP 4, PHP 5)
array_keys — Return all the keys or a subset of the keys of an array
Description
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.
Parameters
- input
-
An array containing keys to return.
- search_value
-
If specified, then only keys containing these values are returned.
- strict
-
Determines if strict comparison (===) should be used during the search.
Return Values
Returns an array of all the keys in input.
Changelog
| Version | Description |
|---|---|
| 5.0.0 | Added the strict parameter. |
Examples
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
)
See Also
- array_values() - Return all the values of an array
- array_key_exists() - Checks if the given key or index exists in the array
- array_search() - Searches the array for a given value and returns the corresponding key if successful