Day 9. Pattern Matching with Regular Expressions

As I'm sure you've noticed, I've been gradually introducing regular expressions since nearly the beginning of this book. In this lesson, it's time to focus our full attention on how regular expressions work. Pattern matching is more than just searching for some set of characters in your data; it's a way of looking at data and processing that data in a manner that can be incredibly efficient and amazingly easy to program. Many Perl programmers use regular expressions in nearly every program that they write.

Today, we'll dive deep into regular expressions, why they're useful, how they're built, and how they work. Tomorrow we'll continue the discussion and cover more advanced uses of regular expressions. Today, specifically, you'll learn

• Understanding pattern matching and regular expressions and why you'll find them useful

• Building simple regular expressions with single-character searches and pattern-matching operators

• Matching groups of characters

• Matching multiple instances of characters

• Using patterns in tests and loops