I am trying to drop a column of a data frame. The code below attempts to drop a numeric column (which does not work but gives no error or warning) and a factor column (which does not work but gives an error). I would appreciate someone telling me why my code does not work, and suggesting code that will work. Thanks, John
rm(dfxyz,dfxz,dfxy) # create the data frame. dfxyz <- data.frame(x=1:10,y=11:20,z=factor(c(rep(0,5),rep(1,5)))) dfxyz names(dfxyz) # try to drop y column # does not work, does not produce error message dfxz <- dfxyz[,-(dfxyz$y)] dfxz # try to drop z column # does not work, produces error message: # In Ops.factor(df$z) : - not meaningful for factors dfxy <- dfxyz[,-dfxyz$z] dfxy John David Sorkin M.D., Ph.D. Chief, Biostatistics and Informatics University of Maryland School of Medicine Division of Gerontology Baltimore VA Medical Center 10 North Greene Street GRECC (BT/18/GR) Baltimore, MD 21201-1524 (Phone) 410-605-7119 (Fax) 410-605-7913 (Please call phone number above prior to faxing) Confidentiality Statement: This email message, including any attachments, is for th...{{dropped:6}} ______________________________________________ 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.