Howdy :)

This is just something that came up in a casual email exchange today. And I've no particular reason for posing the question here other than curiosity, and perhaps providing the opportunity for those with plenty of regex fu to show their stuff :)

"How would you construct a regex to match an integer between 0 and 100?"

My regex fu is only average at best, but after a couple of minutes I came up with:

perl -le 'for (qw/0 1 19 32.4 100 77 138 342.1/) { print "$_ is ", /^(
+?:100|\d\d?)$/ ? "valid input" : "invalid input"}'
[download]

Which gives:

0 is valid input
1 is valid input
19 is valid input
32.4 is invalid input
100 is valid input
77 is valid input
138 is invalid input
342.1 is invalid input
[download]

Solves the "problem", but hard-coding the 100 in the pattern is pretty horrible, I think.

So how would others do this?

Cheers,
Darren

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