(PHP 4 >= 4.0.0)
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 $array = array (0 => 100, "color" => "red");
print_r(array_keys ($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
) |
|
Note:
This function was added to PHP 4, below is an implementation for
those still using PHP 3.
Example 2.
Implementation of array_keys() for PHP 3
users
function array_keys ($arr, $term="") {
$t = array();
while (list($k,$v) = each($arr)) {
if ($term && $v != $term) {
continue;
}
$t[] = $k;
}
return $t;
} |
|
See also array_values().