Santa's Regex to Town

To the bewilderment of my friends and co-workers, regex (or regular expression)is one of my favorite things in the world. Not only is writing them fun (think ciphers!), but they can be extremely useful as well! Today we're going to see how we can use it to help out our pal Santa Clause.

Here is a brief rundown on regular expressions before we get started:

-- What is it?: a sequence of characters that define a search pattern.