The “Break it Down” Blog

Mike Malone put up an excellent introduction to Regular Expressions that I think anyone that is rusty or curious should take a look at. He took the most basic concepts in regexp and introduces you to them in such a way that you could probably accomplish 80% of the matching you would need to without further reading.

The topics Mike covers are:

• The Line Anchors: ^ and $
• The Character Class: []
• The Character Class Metacharacter: -
• Matching Any Character With a Dot: .
• The Alternation Metacharacter: |
• Matching Optional Items: ?
• The Other Quantifiers: + and *
• The Interval Quantifier: {}
• The Escape Character: \
• Using Parenthesis for Matching: ()

I know in the past when I’ve dabbled in regular expressions it’s always been hit-or-miss until I got matching what I wanted, but I never really understood them, or I would understand just enough to finish what I was working on. I think most developers don’t acknowledge the importance of regular expressions or the power of them.

A plugin for Eclipse 3.x that I’ve been using to test regular expressions recently that I find to be excellent is the “Eclipse Regular Expression Tester” plugin. Here is an online one for folks that don’t use Eclipse.