Hi Tony, I "GUESS" my.df[-"DrHorrible"] does not tell R which column "NUMBER" would like to remove. As we know, we could use my.df[-4] and it exactly tells R which column must remvoer from your data.
> my.df[-4] Angel Buffy Firefly 1 7 8 9 2 8 9 9 3 6 4 10 4 9 9 10 5 10 10 10 I may be not right. Chunhao > Date: Sun, 22 Feb 2009 14:48:10 -0800 > From: tony.bre...@googlemail.com > To: r-help@r-project.org > Subject: [R] Filtering a data frame using a string for colum header > > Hi all, > > I was just radomly playing with R and got the following error when > trying to filter a data frame using a string: > > > Angel <- c(7,8,6,9,10) > > Buffy <- c(8,9,4,9,10) > > Firefly <- c(9,9,10,10,10) > > DrHorrible <- c(10,9,9,10,10) > > my.df <- data.frame(Angel, Buffy, Firefly, DrHorrible) > > my.df["DrHorrible"] > DrHorrible > 1 10 > 2 9 > 3 9 > 4 10 > 5 10 > > my.df[-"DrHorrible"] > Error in -"DrHorrible" : invalid argument to unary operator > > > > I know how to work around this problem quite easily, I'm just curious > as to why the my.df[-"DrHorrible] statement didn't work? > > Cheers, > Tony > > OS = win XP > > sessionInfo() > R version 2.8.1 (2008-12-22) > i386-pc-mingw32 > > locale: > LC_COLLATE=English_United Kingdom.1252;LC_CTYPE=English_United Kingdom. > 1252;LC_MONETARY=English_United Kingdom. > 1252;LC_NUMERIC=C;LC_TIME=English_United Kingdom.1252 > > attached base packages: > [1] stats graphics grDevices utils datasets methods > base > > > > ______________________________________________ > 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. _________________________________________________________________ [[elided Hotmail spam]] [[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.
