Thanks! Very glad you pointed me to the paste function, it looks very helpful.
I have a quick follow-up after reading through the online tutorial on the "paste" function: Why do we need quotation marks around "Major Gleason" and "Minor Gleason" in: output = paste(df [,'Major.Gleason'], df[ ,'Minor.Gleason'], sep='+')? The "paste" function is going to concatenate the first and second parameters and separate them by the "+" sign, so I'm not clear why we need to put quotation marks around the dataframe column headers... Thanks, Ben On Mon, Jun 20, 2011 at 11:58 AM, David Winsemius <dwinsem...@comcast.net>wrote: > > On Jun 20, 2011, at 11:47 AM, Luke Miller wrote: > > If we assume that your data are in a data frame (which doesn't allow >> spaces in column names, hence the periods in the call below): >> >> df = data.frame(Major.Gleason = c(4,5,2,3), Minor.Gleason = c(3,2,4,3)) >>> >> >> You can paste together the contents of the two columns with a plus >> sign in between using the paste() function. The sep='' option at the >> end of the function call specifies that no spaces should be included >> between pasted items. >> >> output = paste(as.character(df [,'Major.Gleason']), '+', as.character(df[ >>> ,'Minor.Gleason']), sep='') >>> >> > I do not think the as.character is needed. Coercion to character is > implicit in the use of paste(). And the sep argument could be "+". > > output = paste(df [,'Major.Gleason'], df[ ,'Minor.Gleason'], sep='+') > > -- > David. > > > >> The new object 'output' is a character vector containing the 4 strings >> you're after: >> >> print(output) >>> >> [1] "4+3" "5+2" "2+4" "3+3" >> >> >> On Mon, Jun 20, 2011 at 11:31 AM, Ben Ganzfried <ben.ganzfr...@gmail.com> >> wrote: >> >>> >>> Hi -- >>> >>> I had a pretty quick R question since unfortunately I have not been able >>> to >>> find an answer on Google. It shouldn't take much more than a minute to >>> answer. >>> >>> I'm trying to add up the major gleason grade and minor gleason grade for >>> an >>> analysis of patients with prostate cancer. One column has values under >>> "Major Gleason" and another column has values under "Minor Gleason." For >>> example, >>> Major Gleason Minor Gleason >>> 4 3 >>> 5 2 >>> 2 4 >>> 3 3 >>> >>> I want my output to be: >>> "4+3" >>> "5+2" >>> "2+4" >>> "3+3" >>> >>> The quasi-pseudocode in Java is basically: >>> >>> major = column$majorGleason >>> minor = column$minorGleason >>> for item in len(Major Gleason) { >>> string s = major(item) "+" minor(item); >>> } >>> return s; >>> >>> But trying the same idea in R: >>> >>> string <- major "+" minor >>> >>> gives me an error: "unexpected string constant in..." >>> >>> I would greatly appreciate any help. >>> >>> Thanks, >>> >>> Ben >>> >>> [[alternative HTML version deleted]] >>> >>> ______________________________**________________ >>> R-help@r-project.org mailing list >>> https://stat.ethz.ch/mailman/**listinfo/r-help<https://stat.ethz.ch/mailman/listinfo/r-help> >>> PLEASE do read the posting guide http://www.R-project.org/** >>> posting-guide.html <http://www.R-project.org/posting-guide.html> >>> and provide commented, minimal, self-contained, reproducible code. >>> >> >> >> >> -- >> ___________________________ >> Luke Miller >> Postdoctoral Researcher >> Marine Science Center >> Northeastern University >> Nahant, MA >> (781) 581-7370 x318 >> >> ______________________________**________________ >> R-help@r-project.org mailing list >> https://stat.ethz.ch/mailman/**listinfo/r-help<https://stat.ethz.ch/mailman/listinfo/r-help> >> PLEASE do read the posting guide http://www.R-project.org/** >> posting-guide.html <http://www.R-project.org/posting-guide.html> >> and provide commented, minimal, self-contained, reproducible code. >> > > David Winsemius, MD > West Hartford, CT > > [[alternative HTML version deleted]] ______________________________________________ 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.