On text2re.com, you can input some text you want to use a regular expression on, click on what you want to match, and it’ll generate the regular expression for you.
This system acts as a regular expression generator. Instead of trying to build the regular expression, you start off with the string that you want to search. You paste this into the site, click submit and the site finds recognisable patterns in your string. You then select the patterns that you are interested in and it writes a fully fledged program that extracts those patterns from that string. You then copy the program into your editor or IDE and play with it to integrate it into your program.
This just totally broke my brain.