array_keys

(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.

Note: This function was added to PHP 4, below is an implementation for those still using PHP 3.

See also array_values().