Regular expressions are one of those quirky features that popup in a variety of programming languages, but because they seem to be a difficult concept to grasp, many developers push them away into the corner, forgetting that they even exist.
A regular expression is a specially formatted pattern that can be used to find instances of one string in another. Several programming languages including Visual Basic, Perl, JavaScript and PHP support regular expressions, and hopefully by the end of this primer you should be able to implement some basic regular expression functionality into your PHP pages.
Let's start by taking a look at what a regular expression is, and why you'd want to use them in your PHP pages.
