Re: regexps [was: aterm] - off-topic, wot
Henning Percy (percy@ferndown.tt.slb.com)
Wed, 14 Apr 1999 16:33:56 +0100 (BST)
On Wed, Apr 14, 1999 at 09:46:09AM -0400, Simon Drabble wrote:
> > Does anyone have a regular expression that would identify this:
> > [+|-]digit
> > Testing for a digit or a leading + or - is easy, but I can't
> > come up with a regular expression that will identify a string
> > as a digit that may or may not have a leading plus or minus sign.
> > Thanks.
I'd probably use something like:
([-+]?)([0-9]+)
assuming that it's jsut for integers.
It breaks down like this:
[-+] A plus or minus sign
[-+]? Zero or one plus or minus signs
That's that leading bit done.
[0-9]+ One or more of the characters 0-9.
That's the number bit.
Put brackets round each part, just to make sure and then join them
together gives:
([-+]?)([0-9]+)
This would match the following:
1
+12345
-123
But would not match this:
++12312321
--2356
Hope this helps.
Adler
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