Writing regular expressions about always give me a headache… You probably know about the nice regular-expressions.info website, containing a lot of useful information and what seems to be a fairly exhaustive reference.
Yet it misses a useful tool: a way to test your regex. That’s where regex101 (“Regular Expressions 101”) comes in handy. You simply enter your regular expression, pick modifiers (help available for those), then enter some text and see if the regular expression matches it.
Other interesting features:
– quick regex reference in the bottom right corner
– (very) basic code generator in those languages to use your regular expression
– you can create unit tests
– you can save your stuff either via unique URL or by using a Github or Google (yuck) account. I haven’t tested this, though.