array_walk Usage

Alright, so I was confused by the PHP Docs on array_walk. So, I wrote a little example to try to figure out how it works. I did so because the PHP documentation on the function was a bit unclear in my opinion.

The basic structure for array_walk is:

array_walk( array $myarray, function(&$val, $key) );

That said, you can see my usage here and the corresponding output it provides.