try grep(paste("^",b[2],"$",sep=""),a)
your version will match "b2": > grep("^b[2]$",c("b","b2","b3")) [1] 2 --- Shao <[EMAIL PROTECTED]> wrote: > Hi,everyone. > > I have a problem when using the grep. > for example: > a <- c("aa","aba","abac") > b<- c("ab","aba") > > I want to match the whole word,so > grep("^aba$",a) > it returns 2 > > but when I used it a more useful way: > grep("^b[2]$",a), > it doesn't work at all, it can't find it, returning integer(0). > > How can I chang the format in the second way? > > Thanks. > > -- > Shao > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help@stat.math.ethz.ch 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. > ____________________________________________________________________________________ Pinpoint customers who are looking for what you sell. ______________________________________________ R-help@stat.math.ethz.ch 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.