?regex is a nice starting point, it's got plenty of details on meta characters and characters classes, if you need more advanced stuff you'll probably have to look at the perl regex documentation, I believe it's linked in ?regex.
I might try something like grep("^[xz]\\.") or grep("^[xz][.]") or if you'd consider a different function, startsWith(jj, "x.") | startsWith(jj, "z.") On Sun, Jul 10, 2022, 21:49 Steven T. Yen <st...@ntu.edu.tw> wrote: > Thanks Jeff. It works. If there is a good reference I should read > (besides ? grep) I's be glad to have it. > > On 7/11/2022 9:30 AM, Jeff Newmiller wrote: > > grep( "^(z|x)\\.", jj, value = TRUE ) > > > > or > > > > grep( r"(^(z|x)\.)", jj, value = TRUE ) > > > > > > On July 10, 2022 6:08:45 PM PDT, "Steven T. Yen" <st...@ntu.edu.tw> > wrote: > >> Dear, Below, jj contains character strings starting with “z.” and “x.”. > I want to grep all that contain either “z.” or “x.”. I had to grep “z.” and > “x.” separately and then tack the result together. Is there a convenient > grep option that would grep strings with either “z.” or “x.”. Thank you! > >> > >>> jj<-names(v$est); jj > >> [1] "z.one" "z.liberal" "z.conserv" "z.dem" "z.rep" > "z.realinc" > >> [7] "x.one" "x.liberal" "x.conserv" "x.dem" "x.rep" > "x.realinc" > >> [13] "mu1_1" "mu2_1" "rho" > >>> j1<-grep("z.",jj,value=TRUE); j1 > >> [1] "z.one" "z.liberal" "z.conserv" "z.dem" "z.rep" "z.realinc" > >>> j2<-grep("x.",jj,value=TRUE); j2 > >> [1] "x.one" "x.liberal" "x.conserv" "x.dem" "x.rep" "x.realinc" > >>> j<-c(j1,j2); j > >> [1] "z.one" "z.liberal" "z.conserv" "z.dem" "z.rep" > "z.realinc" > >> [7] "x.one" "x.liberal" "x.conserv" "x.dem" "x.rep" > "x.realinc" > >> > >> ______________________________________________ > >> 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. > [[alternative HTML version deleted]] ______________________________________________ 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.