array_walk, or array_map, or foreach?

PHP List, I took a snippet of code right off the php.net site to use trim on all the elements of an array. Theoretically, it should test if the element in an array is in turn another array, and break it down to the next level until it gets to a string it can use trim on. This is the code: public static function trimArray($array) { if (is_array($array)) { array_walk($array, "trimArray"); } else { $array = trim($array); } return $array; } The function exists inside a static class called "Utility" where I keep all basic utility functions. I don't know if it's the fact that it's in a static class that makes a difference, but I've tried the following variations on the line with array_walk() in it: array_walk($array, "Utlity::trimArray") array_map("Utility::trimArray", $array) array_map("trimArray", $array) I've even tried accomplishing it with a foreach(), but no matter what I do, it doesn't work. As it walks through the array, it seems to trim a copy of the element in the array, trim that, but leave the original array untouched. What am I missing here? -- Dave M G Ubuntu 6.06 LTS Kernel 2.6.17.7 Pentium D Dual Core Processor PHP 5, MySQL 5, Apache 2