Regexper – Regular expressions visualizer
Here's an example of a regex to validate us phone numbers<p><a href="https://regexper.com/#%2F%5E(1%5Cs%3F)%3F(%5B0-9%5D%7B3%7D%7C%5C(%5B0-9%5D%7B3%7D%5C))%5B%5Cs%7C-%5D%3F%5B0-9%5D%7B3%7D%5B%5Cs%7C-%5D%3F%5B0-9%5D%7B4%7D%24%2Fgm" rel="nofollow">https://regexper.com/#%2F%5E(1%5Cs%3F)%3F(%5B0-9%5D%7B3%7D%7...</a><p>From<p><a href="https://www.freecodecamp.org/challenges/validate-us-telephone-numbers" rel="nofollow">https://www.freecodecamp.org/challenges/validate-us-telephon...</a><p>I found these 11 videos most helpful when learning regex from codecourse<p><a href="https://www.youtube.com/watch?v=GVZOJ1rEnUg&index=1&list=PLfdtiltiRHWGRPyPMGuLPWuiWgEI9Kp1w" rel="nofollow">https://www.youtube.com/watch?v=GVZOJ1rEnUg&index=1&list=PLf...</a>