Don't allow the simplicity of the chapter to fool you, what we have learned throughout this chapter will be very useful in your day-to-day work with regex, and it'll give you a lot of leverage.

Let's summarize what we have learned so far. First, we have seen how a group can help us when we need to apply quantifiers to only some part of the expression.

We have also learned how to use the captured groups in the pattern again or even in the replacement string in the sub operation, thanks to backreferences.

In this chapter, we have also viewed named groups, a tool for improving the readability and future maintenance of the regex.

Later on, we have learned to match a subexpression just in case a previous group exists or on the other hand, to match it when a previous group doesn't exist.

Now that we know how to use groups, it's time to learn a more complex subject very close to groups; look around!