Can any one help me to understand Regex?

Question

I don't understand what match is going on?!

Answer 1

After checking the lessons here, let us know what is not clear.
https://www.sololearn.com/learn/9704/?ref=app

Answer 2

https://www.sololearn.com/Discuss/1693914/?ref=app

Answer 3

https://code.sololearn.com/WKFF4vOCr3mi/?ref=app

Danijel has published lots of RegEx tutorials, you can use the filter option on topic for a list of his tutorial