Its a minor optimization but might make a difference if you process large arrays. Built-in PHP function array_walk allows you to apply a function to every element in an array. Obviously you can get the same results using a foreach. One would expect the built-in function to be faster since its written in C and hopefully has been highly optimized but it turns out, that’s not the case. After a bit of online research and some tests, foreach is the clear winner. Here’s the examples:
foreach wins. Case closed.