Infelicity in print output with matrix indexing of `[.data.frame`
It's documented, David:
From ?"[.data.frame"
"Matrix indexing (x[i] with a logical or a 2-column integer matrix i) using [ is not recommended. For extraction, x is first coerced to a matrix..." ergo characters for a mixed mode frame. 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 Sat, Dec 17, 2016 at 10:49 AM, David Winsemius
<dwinsemius at comcast.net> wrote:
This puzzle started with an SO posting where the questioner showed output from a dataframe that had been indexed with a matrix. The output appeared to show that numeric values had been coerced to character. Once I got a reproducible example I discovered that the print output was the problem and that the actual values had not been coerced. I've created a much smaller test case and it appears from the testing below that a matrix indexed output from a dataframe with mixed numeric and character types will be printed as character even if none of the values indexed are character:
dat <- setNames( as.data.frame( matrix(1:12, ncol=4) ), LETTERS[1:4]) dat
A B C D 1 1 4 7 10 2 2 5 8 11 3 3 6 9 12
dat[2,4]<-NA dat[3,3]<-NA ng <- which(is.na(dat), arr.ind=TRUE) ng
row col [1,] 3 3 [2,] 2 4
dat[ng] <- 20 dat[ng]
[1] 20 20 That was as expected. Now repeat the process with a dataframe of mixed types.
dat[2,4]<-NA dat[3,3]<-NA dat[,1]<- "a" dat
A B C D 1 a 4 7 10 2 a 5 8 NA 3 a 6 NA 12
dat[ng] <- 20 dat[ng]
[1] "20" "20" Quoted print output was not what I was expecting. -- David Winsemius Alameda, CA, USA
______________________________________________ R-help at 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.