In PHP, how do you change the key of an array element?

Question

I have an associative array in the form key => value where key is a numerical value, however it is not a sequential numerical value. The key is actually an I

Answer 1

Here is a helper function to achieve that:

/**
 * Helper function to rename array keys.
 */
function _rename_arr_key($oldkey, $newkey, array &$arr) {
    if (array_key_exists($oldkey, $arr)) {
        $arr[$newkey] = $arr[$oldkey];
        unset($arr[$oldkey]);
        return TRUE;
    } else {
        return FALSE;
    }
}

pretty based on @KernelM answer.

Usage:

_rename_arr_key('oldkey', 'newkey', $my_array);

It will return true on successful rename, otherwise false.