On Wed, 2009-07-15 at 14:35 +0000, Tom Liptrot wrote: > > > > Hi R helpers, > > I have a data frame and I want to change the column names to names I have > held in another data frame, but I am having difficulty. All data framnes are > large so i can't input manually. Below is what i have tried so far: > > df<-data.frame(a=1:5, b=2:6, d=3:7, e=4:8) > coltitles<-data.frame(v1="col number one", v2="col number two", v3="col > number three", v4="col number four") > > ##first attempt > > names(df)<-coltitles > names(df) > [1] "1" "1" "1" "1" ###not what i wanted as I want names(df) to return [1] > "col number one" "col number two" "col number three" "col number four" > > > > ##second attempt > > coltitles<-as.vector(coltitles, mode="character") ##trying to convert to a > character vector after looking at help > is.vector(coltitles) > [1] TRUE > names(df)<-coltitles > names(df) > [1] "1" "1" "1" "1" ###again not what I wanted > > How can I convert the column names?
This seems a bit of a strange way to go about things, but if needs must: > names(df) <- unlist(coltitles) > df col number one col number two col number three col number four 1 1 2 3 4 2 2 3 4 5 3 3 4 5 6 4 4 5 6 7 5 5 6 7 8 > names(df) [1] "col number one" "col number two" "col number three" "col number four" If your data frame with the names in the one (and only) row (why store this as a one row df and not a character vector??? [1]) then by unlisting it we get a (or something that can be coerced to) a character vector of the correct names. If coltitles contains more rows, then: names(df) <- unlist(coltitles[1,]) might be more appropriate. HTH G [1] Your df storage of names is soooo inefficient (for this task): > object.size(names(df)) # after running the above code 312 bytes > object.size(coltitles) 2728 bytes > > Thanks in advance, > > Tom > > Beyond Hotmail - see what else you can do with Windows Live. Find out more. > _________________________________________________________________ > > > [[alternative HTML version deleted]] > > ______________________________________________ > [email protected] 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. -- %~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~% Dr. Gavin Simpson [t] +44 (0)20 7679 0522 ECRC, UCL Geography, [f] +44 (0)20 7679 0565 Pearson Building, [e] gavin.simpsonATNOSPAMucl.ac.uk Gower Street, London [w] http://www.ucl.ac.uk/~ucfagls/ UK. WC1E 6BT. [w] http://www.freshwaters.org.uk %~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~% ______________________________________________ [email protected] 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.
