If you want to only match names of length 6, you will have to use this pattern:
> x <- c("ZFHSJK", "ZFHJKZ","ZIOPWE","ZLKJSD","ZKFLPZ", "ZAAAAAAZ", "ZAZ", + "ZAAAAZAZ", "ZRITEZ") > # match exactly values of length 6 > len6 <- "^Z[[:alpha:]]{4}Z$" > grep(len6, x) [1] 2 5 9 > On Sun, May 22, 2011 at 5:10 PM, Kang Min <ngokang...@gmail.com> wrote: > Thanks! > > On May 21, 7:09 am, David Winsemius <dwinsem...@comcast.net> wrote: >> On May 20, 2011, at 11:57 AM, Kang Min wrote: >> >> > Hi all, >> >> > I'm trying to subset a pattern in a vector. Each argument has 6 >> > letters, and I need those that start with Z and end with Z. >> >> > e.g. >> > x <- c("ZFHSJK", "ZFHJKZ","ZIOPWE","ZLKJSD","ZKFLPZ") >> >> > I've looked up other discussions but still can't seem to find the >> > answer. >> >> You may need to study the regex page a bit longer >> >> the "^" is the beginning of a string >> ".+" will math can arbitrarily long string of anything >> and "$" indicates the end of a string >> >> > x <- c("ZFHSJK", "ZFHJKZ","ZIOPWE","ZLKJSD","ZKFLPZ") >> > grep("^Z.+Z$", x) >> [1] 2 5 >> > grep("^Z.+Z$", x, value=TRUE) >> [1] "ZFHJKZ" "ZKFLPZ" >> >> >> >> > Thanks. >> > Kangmin >> >> > ______________________________________________ >> > r-h...@r-project.org mailing list >> >https://stat.ethz.ch/mailman/listinfo/r-help >> > PLEASE do read the posting guidehttp://www.R-project.org/posting-guide.html >> > and provide commented, minimal, self-contained, reproducible code. >> >> David Winsemius, MD >> West Hartford, CT >> >> ______________________________________________ >> r-h...@r-project.org mailing listhttps://stat.ethz.ch/mailman/listinfo/r-help >> PLEASE do read the posting guidehttp://www.R-project.org/posting-guide.html >> and provide commented, minimal, self-contained, reproducible code. > > ______________________________________________ > 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. > -- Jim Holtman Data Munger Guru What is the problem that you are trying to solve? ______________________________________________ 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.