On PHPBuilder.com there's a new installment in their "ABCs of PHP" series posted - a look at working with regular expressions.
We've looked at strings, and numbers and all sorts of types of data, but we've not yet seen how to do something really important, and that's to look for and pull interesting parts out of the data we have, to do that where going to use some magic from the Perl world called "Regular Expressions".
They start simple by looking at what regular expressions are and how they work to match portions (or all) of a string. Thankfully, they chose to go with the preg_* functions (like preg_match and friends) for their matching over the ereg_* functions. They talk about direct matches, wildcards and partial matching.