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Regex Isn't Hard (2023)

(timkellogg.me)
75 points asicsp | 2 comments | 21 Apr 25 10:35 UTC | HN request time: 0.453s | source
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michaelt ◴[21 Apr 25 11:01 UTC] No.43750496[source]▶
> e.g. This pattern ([0-9][0-9]?[0-9]][.])+ matches one, two or three digits followed by a . and also matches repeated patterns of this. This wold match an IP address (albeit not strictly).

I love regular expressions but one thing I've learned over the years is the syntax is dense enough that even people who are confident enough to start writing regex tutorials often can't write a regex that matches an IP address.

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1. iugtmkbdfil834 ◴[21 Apr 25 11:05 UTC] No.43750531[source]▶
Is it because everyone tries to make it look short?

edit: asking partly, because in my current work I occassionally have to convince non-technical users to use one type of entry over other. For that reason, easy to read, simple regex wins over fancy, but convoluted regex.

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2. vitus ◴[21 Apr 25 11:40 UTC] No.43750783[source]▶
> For that reason, easy to read, simple regex wins over fancy, but convoluted regex.

Sure, I'd take \d+\.\d+\.\d+\.\d+ over... "((2(5[0-5]|[0-4][0-9])|1[0-9]{2}|[1-9]?[0-9])\.){3}(2(5[0-5]|[0-4][0-9])|1[0-9]{2}|[1-9]?[0-9])", assuming that I then validate the results afterwards.