First, let's say in few words what are regular expressions, at times abbreviated regexps or regexes :
Regular expressions are sequences of characters that define a search pattern.
The cool thing is that basically all modern programming languages use them!
Rubular
Rubular is a web app that lets you practice regexes in Ruby. It’s a handy way to test regular expressions as you write them!
HackerRank
HackerRank is a community of over 16 Millions developers. It will help you practice regexes, general coding skills in different coding languages and prepare for interview to land a developer job.
W3Resource
On W3Resource you will practice regexps in Python solving 56 exercises with solutions.
