Mention myregextester.com when discussing regular expressions

[pdurbin]

My favorite resource for explaining regular expressions is https://myregextester.com

You might consider playing with it (especially the "explain" option) and adding it to http://tutorials.iq.harvard.edu/R/RProgramming/Rprogramming.html

Here's a sample screenshot:

I believe the output comes from http://search.cpan.org/dist/YAPE-Regex-Explain/Explain.pm which one could install locally.

[izahn]

That looks a bit old fashioned, and there seems to be a problem with the ssl certificate. How about http://www.regexr.com/ instead?

[pdurbin]

Well, I can't find any "explain" feature on http://www.regexr.com . That was the point of https://myregextester.com and http://search.cpan.org/dist/YAPE-Regex-Explain/Explain.pm in my mind, the killer feature.

[pdurbin]

Oooo, "Roll over a match or expression for details." That was a bit subtle for me. I can't tell if there's a command line mode from a quick look at https://github.com/gskinner/regexr but the GUI seems nice: