The merge function combines 2, not 3 files at a time. Maybe rich.stats2 = merge(rich.stats, Month, by="X.SampleID") rich.stats3 = merge(rich.stats2, Location, by="X.SampleID")
Reading the manual page will help: ?merge ------------------------------------- David L Carlson Department of Anthropology Texas A&M University College Station, TX 77840-4352 -----Original Message----- From: R-help [mailto:r-help-boun...@r-project.org] On Behalf Of Lauren O'Connell Sent: Wednesday, March 11, 2015 11:02 AM To: r-help@r-project.org Subject: [R] Adding Column to a Data Frame I am trying to add a column with data to a data frame that already has information but am getting this error: > rich.stats4 = merge(rich.stats,Location,Month,by="X.SampleID") Error in fix.by(by.x, x) : 'by' must specify one or more columns as numbers, names or logical I have two separate data frames that contain my sample names with location and with month: #Create data frame of all sample names and month sample was taken Month = data.frame(X.SampleID=sample_data(Lauren5000)$X.SampleID,MonthSampleTaken=sample_data(Lauren5000)$MonthSampleTaken) head(Month) #Create data frame of all samples names and location of sample Location = data.frame(X.SampleID=sample_data(Lauren5000)$X.SampleID,Location=sample_data(Lauren5000)$Location) head(Location) I was able to add my "MonthSampleTaken" variable by using this command: >rich.stats2 = merge(rich.stats, Month,by="X.SampleID") > head(rich.stats2) X.SampleID mean sd MonthSampleTaken 1 PE101 1421.34 19.44961 February 2 PE102 1336.24 25.43882 February 3 PE104 1418.75 21.92889 March 4 PE105 1331.03 20.55712 March 5 PE107 1320.21 20.91942 March 6 PE108 1328.41 20.49247 March I now want to add my sample site location, but can't figure out how to do this. Any help would be greatly appreciated. Cheers, Lauren [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see 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. ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see 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.