Why (?<!peer.*)210 does not work in UltraEdit search?

wenchunyu · Sep 06, 2016#12016-09-06T16:34+00:00

The text:

: peeripaddress=10.20.227.210
 peer2fsafd=210
(92):
Schedtutler 2=210666666
213e=210
213ddress=10.20.227.sdfsdf210dsd
213address=10.20.227.vcxv210112
213address=10.20.227.210
213address=10.20.227.210

I want to find only 210 on lines not containing also the word peer, but (?<!peer.*)210 does not work in UltraEdit. But I tested the expression in Regular Expressions test tools and there it worked. So how to make it working?

Mofi · Sep 07, 2016#22016-09-07T05:05+00:00

The Perl regular expression library must be able on a lookbehind to find out how much characters it has to read back from beginning of found text to test against the lookbehind expression. With .* inside the lookbehind the number of characters to read back from position where 210 is found can't be determined. This Perl regular expression is therefore invalid. Please read on Lookahead and Lookbehind Zero-Length Assertions at least the section Important Notes About Lookbehind.

fleggy · Sep 07, 2016#32016-09-07T07:56+00:00

Hi,

perhaps this is what you are looking for:

^(?=(?>.(?<!peer))*?210).*\K210

BR, Fleggy

wenchunyu · Sep 07, 2016#42016-09-07T13:50+00:00

Fleggy, yes it is, thanks, you are great.

fleggy · Sep 07, 2016#52016-09-07T18:04+00:00

The expression is unnecessarily complicated. The simpler version is:

^(?>.(?<!peer))*?\K210

But it works only if peer precedes 210, so if you want to find 210 on lines not containing peer at all then use this, please:

^(?>.(?<!peer))*?\K210(?=(.(?<!peer))*$)

BR, Fleggy