array_keys
(PHP 4 )
array_keys -- Return all the keys of an array
Description
array
array_keys ( array input [, mixed search_value])
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.
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 printout of the program above will be:
Array
(
[0] => 0
[1] => color
)
Array
(
[0] => 0
[1] => 3
[2] => 4
)
Array
(
[0] => color
[1] => size
) |
|
See also array_values() and
array_key_exists().