> On May 3, 2016, at 11:16 PM, Jeff Newmiller <jdnew...@dcn.davis.ca.us> wrote: > > Yes, but the answer is likely to depend on the actual patterns of strings in > your real data, so the sooner you go find a book or tutorial on regular > expressions the better. This is decidedly not R specific and there are > already lots of resources out there. > > Given the example you provide, the pattern "age$" should work. However, that > is probably not sufficiently selective for a practical data set so start > learning to fish (design regex patterns) yourself.
@ Steven; As is almost always the case I agree with Jeff. I found that reading Rhelp and attempting to answer regex-questions was the best method to learn them. In particular I found the postings by Gabor Grothendieck very helpful in getting some degree of competence in this area. I see that his grep-related postings still exceed my grep postings and I assure you that his will be more sophisticated than my efforts. I recommend the MarkMail Rhelp mirror interface as very useful in "mining" Rhelp for knowledge: Gabor Grothendieck answers with either 'grep' pr 'regex' in their body: http://markmail.org/search/?q=list%3Aorg.r-project.r-help+list%3Agrep+list%3Aregex+from%3A%22Gabor+Grothendieck -- Happy searching; David. > -- > Sent from my phone. Please excuse my brevity. > > On May 3, 2016 10:45:42 PM PDT, Steven Yen <sye...@gmail.com> wrote: >> Dear all >> In the grep command below, is there a way to identify only "age" and >> not "age2"? In other words, I like to greb "age" and "age2" >> separately, one at a time. Thanks. >> >> x<-c("abc","def","rst","xyz","age","age2") >> x >> >> [1] "abc" "def" "rst" "xyz" "age" "age2" >> >> grep("age2",x) >> >> [1] 6 >> >> grep("age",x) # I need to grab "age" only, not "age2" >> >> [1] 5 6 >> David Winsemius Alameda, CA, USA ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see 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.
