I have another question - I'd like to extract dates from a vector of yyyy-mm-dd, so I just want the dd.
x <- round(runif(10)*100000, digits=0) y <- as.Date(x, origin="1970-01-01") I tried this based on the code that Jim provided, but it just printed the whole date. I think I just need to tweak it a little, but haven't been able to figure it out. y[grep("[[:digit:]]{2}$", y)] Thanks. Kang Min On May 23, 7:22 am, jim holtman <jholt...@gmail.com> wrote: > If you want to only match names of length 6, you will have to use thispattern: > > > x <- c("ZFHSJK", "ZFHJKZ","ZIOPWE","ZLKJSD","ZKFLPZ", "ZAAAAAAZ", "ZAZ", > > + "ZAAAAZAZ", "ZRITEZ") > > > > > > > > > > > # match exactly values of length 6 > > len6 <- "^Z[[:alpha:]]{4}Z$" > >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 apatternin 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-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. > > -- > Jim Holtman > Data Munger Guru > > What is the problem that you are trying to solve? > > ______________________________________________ > 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.