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Re: what is the regular expression that matches nothing?
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From: |
me |
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Subject: |
Re: what is the regular expression that matches nothing? |
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Date: |
24 Dec 2004 02:51:39 GMT |
* Randy Yates:
> Then this is the regular expression that matches *everything*.
Suddenly *everything* and *nothing* look very similar.
> I'm looking for the opposite. I tried using the complement operator
> ("[^...]") but it appears to only operate on arguments inside the
> brackets.
Why don't you search for something random and large(ish) several times?
/(xjwp=qy@9e\.soktt!h{33}wlT4f,Ek>agC%Bpk)\1\1\1\1\1\1\1/
This one matches 8 repetitions of that thing above (including the 33
straight 'h's)
> By the way, a regular expression is a regular expression is a regular
> expression. If it works for grep, it should work for xemacs.
Some regular expressions are more regular than others :-)
- what is the regular expression that matches nothing?, Randy Yates, 2004/12/23
- Re: what is the regular expression that matches nothing? -- I think it is the null expression. When I do "egrep '' somefile" the result is the same as when I do "cat somefile". The result of "egrep -v '' somefile" is, as expected, nothing. HTH, me, 2004/12/23
- Re: what is the regular expression that matches nothing? -- I think it is the null expression. When I do "egrep '' somefile" the result is the same as when I do "cat somefile". The result of "egrep -v '' somefile" is, as expected, nothing. HTH, Randy Yates, 2004/12/23
- Re: what is the regular expression that matches nothing?,
me <=
- Re: what is the regular expression that matches nothing? -- I think it is the null expression. When I do "egrep '' somefile" the result is the same as when I do "cat somefile". The result of "egrep -v '' somefile" is, as expected, nothing. HTH, Stan Brown, 2004/12/23
- Re: what is the regular expression that matches nothing? -- I think it is the null expression. When I do "egrep '' somefile" the result is the same as when I do "cat somefile". The result of "egrep -v '' somefile" is, as expected, nothing. HTH, Randy Yates, 2004/12/24
- Re: what is the regular expression that matches nothing? -- I think it is the null expression. When I do "egrep '' somefile" the result is the same as when I do "cat somefile". The result of "egrep -v '' somefile" is, as expected, nothing. HTH, Andrei Voropaev, 2004/12/27
Re: what is the regular expression that matches nothing?, Paul Jarc, 2004/12/27