> On Mar 21, 2017, at 6:31 PM, Bert Gunter <bgunter.4...@gmail.com> wrote: > > It is not clear to me what you mean, but: > >> grep ("x1 \\+.* \\+ x3",test, value = TRUE) > [1] "x1 + x2 + x3" > > ## This will miss "x1 + x3" though.
So then this might be acceptable: grep ("x1\\ \\+.* x3", test, value = TRUE) > > seems to do what you want, maybe. Perhaps you need to read up about > regular expressions and/or clarify what you want to do. > > > Cheers, > Bert > Bert Gunter > > "The trouble with having an open mind is that people keep coming along > and sticking things into it." > -- Opus (aka Berkeley Breathed in his "Bloom County" comic strip ) > > > On Tue, Mar 21, 2017 at 4:50 PM, Joe Ceradini <joecerad...@gmail.com> wrote: >> Hi Folks, >> >> Is there a way to find "x1 + x2 + x3" given "x1 + x3" as the pattern? >> Or is that a ridiculous question, since I'm trying to find something >> based on a pattern that doesn't exist? >> >> test <- c("x1", "x2", "x3", "x1 + x2 + x3") >> test >> [1] "x1" "x2" "x3" "x1 + x2 + x3" >> >> grep("x1 + x2", test, fixed=TRUE, value = TRUE) >> [1] "x1 + x2 + x3" >> >> >> But what if only have "x1 + x3" as the pattern and still want to >> return "x1 + x2 + x3"? >> >> grep("x1 + x3", test, fixed=TRUE, value = TRUE) >> character(0) >> >> I'm sure this looks like an odd question. I'm trying to build a >> function and stuck on this. Rather than dropping the whole function on >> the list, I thought I'd try one piece I needed help with...although I >> suspect that this question itself probably does bode well for my >> function :) >> >> Thanks! >> Joe >> >> ______________________________________________ >> 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. > > ______________________________________________ > 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. 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.