Array Functions
PHP Manual

array_change_key_case

Changes the case of all keys in an array

Description

array array_change_key_case(array $array, int $case = CASE_LOWER)

Returns an array with all keys from array lowercased or uppercased. Numbered indices are left as is.

Parameters

array

The array to work on

case

Either CASE_UPPER or CASE_LOWER (default)

Return Values

Returns an array with its keys lower or uppercased.

Examples

Example #1 array_change_key_case example

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

The above example will output:

Array
(
    [FIRST] => 1
    [SECOND] => 4
)

Notes

Note:

If an array has indices that will be the same once run through this function (e.g. "keY" and "kEY"), the value that is later in the array will override other indices.