Ok then this code didn't do what I wanted. I want "not including 'arg' before '.symptom'", not individual letters of "arg", but rather as a word.
Bill Dunlap suggested using invert=T, it works for single 1 condition, but not for 2 conditions here: not including "arg" before ".", but at the same time, does include ".symptom". Any other suggestions would be appreciated John ________________________________ From: Peter Langfelder <peter.langfel...@gmail.com> Cc: Bernd Weiss <bernd.we...@uni-koeln.de>; r-help@r-project.org Sent: Thu, March 31, 2011 5:55:26 PM Subject: Re: [R] regular expression > Thanks Bernd! I tried your approach with my real example, sometimes it worked, > sometimes it didn't. For example > > grep('[^(arg)]\\.symptom',"stomach.symptom",value=T) > [1] "stomach.symptom" > > grep('[^(arg)]\\.symptom',"liver.symptom",value=T) > character(0) > > I think both examples should return the text, but the 2nd example didn't. > > What was wrong here? Operator error :) Since you exclude 'r' before the '.', liver.symptom does not match the pattern. Peter [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.