Entry

How do you enter a numeric range (e.g. 0-255) in an RE when matching?

Mar 27th, 2003 09:32
Michael Chermside, Brandon Ade,

You've heard the old saying "When all you have is a hammer, the world 
looks like a nail." Well, in this vein, regular expressions are kind of 
like a swiss army knives. They seem like they can be used for just 
about anything, but they're hardly ever the best tool for the job.
It is unlikely that you actually want to use a RE for anything which 
involves recognizing numbers *and caring what the values are*. So 
consider carefully what you're doing and whether you're better off 
using a parser, or some other such tool.
But if you're convinced you want a regular expression (and I'm guessing 
you're thinking about the classic problem of a RE to describe an IP 
address here), then here's an answer:
    "[0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5]"
Ugly, but it works.
-- Michael Chermside