When in doubt, make your regexes non-greedy. You'll stay out of a lot of trouble that way.

Wow. I found this answer disappointing, dws. There are too many beginners who, once they learn about minimal matching, use it far too often.

The common example is using a non-greedy quantifier instead of greedily matching a negated character class. For example, /"[^"]*"/ is much better than using /".*?"/ to do the same thing. I should probably re-read MRE again as it has been 3 or 4 years but I think it illustrates that removing beginning and trailing whitespace with s/^\s*(.*?)\s*$/$1/ is several times slower than s/^\s*//; s/\s*$//; is.

Revisiting the original question, I suspect a mixed solution like, /(\d+)\D*?to\D*(\d+)/ would actually be better, depending, of course, on whether you defined better as shorter, faster, or easier to understand. I'm not sure though. Like I said, it's been too long since I've read MRE. I'm sure someone here could give us a concise analysis.

I am interested in understanding why you suggest the rule of thumb that you do but I think I'll still agree with Arien on this point. You'll only stay out of trouble by not being in doubt. 

-sauoq
"My two cents aren't worth a dime.";

In reply to Re^4: $1 and regex by sauoq
in thread $1 and regex by Anonymous Monk

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