Ask HN: How did you learn Regex?

1

RegExr

Learned regex in the 90's from the Perl documentation, or possibly one of the oreilly perl references. That was a time where printed language references were more convenient than searching the internet. Perl still includes a shell component for accessing it's documentation, that was invaluable in those ancient times. Perl's regex documentation is rather fantastic. `perldoc perlre` from your terminal. Or https://perldoc.perl.org/perlre A simple way to test a regex you're building is this website, which offers immediate parsing and documentation of your regex, lets you test it against various inputs, and lets you choose which language's regex parser you are targeting. https://regexr.com/.

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2

RegexOne

Start with https://regexone.com/ fun puzzle style interactive tutorial to grasp the basics. After that it's the matter of either it using it with your CLI tools or applying it to problems you are working on.

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3

rubular

I read a lot on https://www.regular-expressions.info and experimented on https://rubular.com since I was also learning Ruby at the time. https://regexr.com is another good tool that breaks down your regex and matches. One of the things I remember being difficult at the beginning was the subtle differences between implementations, like `^` meaning "beginning of line" in Ruby (and others) but meaning "beginning of string" in JavaScript (and others). If you're just starting out, it'd be helpful to read about how a regex engine evaluates an expression against a string so that you can understand the "order of operations" and how repeating elements are matched.

#Regular Expressions #Programming Tools #Development 36 social mentions

4

Regex Crossword

The Regex Crossword was the first thing that made it click for me: https://regexcrossword.com/.

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5

Regexper

That's my go-to these days, but sometimes I like to see a diagram from this one: https://regexper.com I've just slowly learnt it by experimenting with it over the past few years. People have mostly mentioned matching, but I use it more for string manipulation. I'm still not as intermediate a programmer as I'd like to be, so it's great when I need to invert a design decision for example. A similar code structure in multiple places, maybe across multiple files. It also means I don't miss anything, like I would if I did it manually.

#Regular Expressions #Programming Tools #Development 24 social mentions