What does ?: do in regex

Question

I have a regex that looks like this

/^(?:\\w+\\s)*(\\w+)$*/

What is the ?:?

Answer 1

Further to the excellent answers provided, its usefulness is also to simplify the code required to extract groups from the matched results. For example, your (\w+) group is known as group 1 without having to be concerned about any groups that appear before it. This may improve the maintainability of your code.