The OP cannot be entirely blamed for thinking that x[,-"ColName"] would omit x's "ColName" from the result. Base R and many packages have commonly used functions that do context-sensitive (aka 'nonstandard') evaluation.

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E.g. subset() evaluates each argument in a different way: > subset(data.frame(ColA=1:3,ColB=-(11:13)), -ColB>11, -ColA) ColB 2 -12 3 -13 Bill Dunlap TIBCO Software wdunlap tibco.com On Wed, Sep 21, 2016 at 7:45 AM, Bert Gunter <bgunter.4...@gmail.com> wrote: > No, Rui, your example misses the point. Your initial sentence hits it. > > The OP needs to carefully read > ?"[" > and/or spend some time with a suitable R tutorial to learn proper > syntax for subscripting. Asking foolish questions in lieu of doing her > homework seems wrongheaded to me. Others may disagree, of course. > > Cheers, > Bert > > > > > Cheers, > Bert > Bert Gunter > > "The trouble with having an open mind is that people keep coming along > and sticking things into it." > -- Opus (aka Berkeley Breathed in his "Bloom County" comic strip ) > > > On Wed, Sep 21, 2016 at 1:26 AM, <ruipbarra...@sapo.pt> wrote: > > Hello, > > > > The error message means exactly what it says. The operator '-' is > > unary and cannot be followed by a non-numeric atomic object (a vector). > > Try for instance > > > > x <- list(a=1:10, b=rnorm(5)) > > -x > > > > Rui Barradas > > > > > > Citando Pauline Laïlle <pauline.lai...@gmail.com>: > > > >> Works like a charm, thanks! Still don't know what that error message > >> means though. Any idea? > >> > >> 2016-09-20 20:13 GMT+02:00 <ruipbarra...@sapo.pt>: > >>> Sorry, I've made a stupid mistake. > >>> It's obviously the other way around. > >>> > >>> ix <- which(rownames(data) %in% c("601", "604")) > >>> clean <- data[-ix, ] > >>> > >>> Rui Barradas > >>> > >>> Citando ruipbarra...@sapo.pt: > >>>> Hello, > >>>> > >>>> Try something like the following. > >>>> > >>>> ix <- which(c("601", "604") %in% rownames(data)) > >>>> clean <- data[-ix, ] > >>>> > >>>> Hope this helps, > >>>> > >>>> Rui Barradas > >>>> > >>>> Citando Pauline Laïlle <pauline.lai...@gmail.com>: > >>>> > >>>>> Dear all, > >>>>> > >>>>> I built a dataframe with read.csv2(). Initially, row names are > integers > >>>>> (order of answers to a survey). They are listed in the csv's first > column. > >>>>> The import works well and my dataframe looks like I wanted it to > look. > >>>>> > >>>>> Row names go as follows : > >>>>> [1] "6" "29" "31" "32" "52" "55" "63" "71" "72" "80" > "88" "89" > >>>>> "91" "93" "105" "110" "111" "117" "119" "120" > >>>>> [21] "122" "127" "128" "133" "137" "140" "163" "165" "167" "169" > "177" > >>>>> "178" "179" "184" "186" "192" "193" "200" "201" "228" > >>>>> etc. > >>>>> > >>>>> I would like to drop rows "601" & "604" to clean the dataframe. > >>>>> > >>>>> While data["601",] shows me the first row i'd like to drop, > data[-"601",] > >>>>> returns the following : > >>>>> Error in -"601" : invalid argument to unary operator > >>>>> > >>>>> idem with data[c("601","604"),] and data[-c("601","604"),] > >>>>> > >>>>> It is the first time that I run into this specific error. After > reading a > >>>>> bit about it I still don't understand what it means and how to fix > it. > >>>>> > >>>>> Thanks for reading! > >>>>> Best, > >>>>> Pauline. > >>>>> > >>>>> [[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. > >>> > >>> > > > > > > > > [[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. [[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.