array_keys

(PHP4 )

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")

$array = array (1, 100, 2, 100);
array_keys ($array, 100);  //  returns array (0, 2) 
      

See also array_values().