Re: [R] "invalid argument to unary operator" while selecting rows by name

Hello, data["601",] doesn't generate an error because you can also refer to a row by its name, as an alternative to refering to it by row number. It's the same with vectors, just consider the following case. (x <- c("601"=1, b=2)) x[1] x["601"] # the same But when you want to remove it

Re: [R] "invalid argument to unary operator" while selecting rows by name

Tanks for all your answers and for taking the time to help me better understand my mistake. I will take your advice and do some reading! Best, P. Le mercredi 21 septembre 2016, William Dunlap a écrit : > The OP cannot be entirely blamed for thinking that x[,-"ColName"] >

Re: [R] "invalid argument to unary operator" while selecting rows by name

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 : > 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, ]

Re: [R] "invalid argument to unary operator" while selecting rows by name

Hi, thanks for the answer. In this case, the row named "601" is not the 601st row of the table, but the 117th. data[601,] actually refers to a non existing row. I was wondering why data[-"601,] generates an error message whereas data["601",] does not? 2016-09-20 19:08 GMT+02:00 Bert Gunter

Re: [R] "invalid argument to unary operator" while selecting rows by name

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. E.g. subset() evaluates each argument in a different way: >

Re: [R] "invalid argument to unary operator" while selecting rows by name

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

Re: [R] "invalid argument to unary operator" while selecting rows by name

> > Works like a charm, thanks! Still don't know what that error message > > means though. Any idea? You tried to negate a character string. -"601" '-' can't do that. [-x] relies on negative _numbers_ to remove elements, not on separate interpretation of '-' and 'x'. S Ellison

Re: [R] "invalid argument to unary operator" while selecting rows by name

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 : > Works like a charm, thanks!

Re: [R] "invalid argument to unary operator" while selecting rows by name

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 <-

Re: [R] "invalid argument to unary operator" while selecting rows by name

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 : Dear all, I built a dataframe with read.csv2(). Initially, row names are integers (order of

Re: [R] "invalid argument to unary operator" while selecting rows by name

Hint: "601" is not 601. Have you gone through any R tutorials? 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 Tue, Sep 20, 2016 at 5:42 AM,

[R] "invalid argument to unary operator" while selecting rows by name

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"