array_change_key_case

Description

array_change_key_case() changes the keys in the input array to be all lowercase or uppercase. The change depends on the last optional case parameter. You can pass two constants there, CASE_UPPER and CASE_LOWER. The default is CASE_LOWER. The function will leave number indices as is.

$input_array = array("FirSt" => 1, "SecOnd" => 4);
print_r(array_change_key_case($input_array, CASE_UPPER);