Understand Regular Expressions

To begin this series, let's zoom out for a few moments, and review what regular expressions look like, how we can write our own, and what that might look like in our PHP code.

Let's slow down a bit, and focus on a silly example, that will allow us to review such topics as alternation, optional sequences, and non-capturing groups.

Character sets allow us to match any one token, out of a group of characters. As you'll find, this can be incredibly powerful. Let me show you.

Using a practical, real world example, let's review regular expression greediness in this episode.

Often, you'll find yourself in the position of needing to match a set of characters only if they are proceeded or preceded by another sequence. When writing regular expressions, we can use lookaheads and lookbehinds to allow for this.

So far, we've mostly been focusing on the regular expression syntax. But, now, let's switch over to PHP and learn about the various regex-specific functions that are available to us.