This is not restricted to single matches: > colnames(iris) [1] "Sepal.Length" "Sepal.Width" "Petal.Length" "Petal.Width" "Species" > regexpr("Sepal", colnames(iris)) > 0 [1] TRUE TRUE FALSE FALSE FALSE
On 5/30/06, Guo Wei-Wei <[EMAIL PROTECTED]> wrote: > Thank you. I made a mistake in my previous email. What I mean is: > > data.new[,"G1"] <- (data.old[,"XG1"] + data.old[,"YG1"])/2 > > data.old[, regexpr("G1", colnames(data.old)) > 0] > is a nice way, but there are about 100 "X*"s and "Y*"s. Can I do some > comparision on all those column names and get columns with similar > parts? > > 2006/5/31, Gabor Grothendieck <[EMAIL PROTECTED]>: > > On 5/30/06, Guo Wei-Wei <[EMAIL PROTECTED]> wrote: > > > Dear all, > > > > > > I have a data.frame which has names as following. > > > [1] "XG1" "YG1" "XEST" "YEST" > > > [2] "XNOEMP1" "XNOEMP2" "YNOEMP1" "YNOEMP2" > > > [3] "XBUS10" "XBUS10A" "XBUS10B" "XBUS10C" > > > [4] "YBUS10" "YBUS10A" "YBUS10B" "YBUS10C" > > > [5] "XOWNBUS" "XSELFEST" "YOWNBUS" "YSELFEST" > > > > > > Those columns have names beginning with "X" or "Y". Each "X" is paired > > > by a "Y", e.g. "XG1" and "YG1", but they are not in the order of "X Y > > > X Y ...". I want to combine "X*" and "Y*" like this: > > > > > > data.new[,"G1"] <- (data.old[,"XG1"] + endata.use[,"YG1"])/2 > > > > > > How to choose columns by parts of names? For example, I can pick out > > > XG1 and YG1 because they have the common part "G1". > > > > > > > > > This gives all columns whose column name contains G1: > > > > data.old[, regexpr("G1", colnames(data.old)) > 0] > > > > ______________________________________________ > 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 > ______________________________________________ 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