array_keys
Return all the keys of an array
Description
arrayarray_keys
arrayinput
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.
<function>array_keys</function> example
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:
0
[1] => color
)
Array
(
[0] => 0
[1] => 3
[2] => 4
)
Array
(
[0] => color
[1] => size
)
]]>
This function was added to PHP 4, below is an implementation for
those still using PHP 3.
Implementation of <function>array_keys</function> for PHP 3
users
See also array_values.