Hi r-help-boun...@r-project.org napsal dne 23.02.2009 03:44:41:
> > 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. It is a bit deeper than [] selection. > -"DrHorrible" Error in -"DrHorrible" : invalid argument to unary operator, so the error is within selection operator [...]. If you know the name and you do not want column with this particular name use my.df[,!names(my.df)==("DrHorrible")] Regards Petr > > > > 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. ______________________________________________ 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.