This is a simple way to get a subset of associative array elements using an array of keys; basically you extract out the elements you want from a bigger array by listing the keys you need. Continue reading
When working with regular expressions, it can be difficult to understand why a particualar pattern is not working as you would expect.
The visual debug tool at debuggex.com makes it much easier to step through and actually visualize how a pattern is working or, as is often the case, not working.
Here is an overview of how it works.
Love this simple and well illustrated guide to some github basics: http://rogerdudler.github.io/git-guide/