(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
$array = array (0 => 100, "color" => "red");
array_keys ($array); // returns array (0, "color")
$array = array ("blue", "red", "green", "blue", "blue");
array_keys ($array, "blue"); // returns array (0, 3, 4)
$array = array ("color" => array("blue", "red", "green"), "size" => array("small", "medium", "large"));
array_keys ($array); // returns array ("color", "size")
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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;
}
}
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See also array_values().