Борис, Try this where you tell matrix the column names you want:
nouns <- as.data.frame( matrix(c( "gaggle", "geese", "dule", "doves", "wake", "vultures" ), ncol = 2, byrow = TRUE, dimnames=list(NULL, c("collective", "category")))) Result: > nouns collective category 1 gaggle geese 2 dule doves 3 wake vultures The above simply names the columns earlier when creating the matrix. There are other ways and the way you tried LOOKS like it should work but fails for me with a message about it weirdly expecting three rows versus two which seems to confuse rows and columns. My version of R is recent and I wonder if there is a bug here. Consider whether you really need the data.frame created in a single statement or can you change the column names next as in: > nouns V1 V2 1 gaggle geese 2 dule doves 3 wake vultures > colnames(nouns) [1] "V1" "V2" > colnames(nouns) <- c("collective", "category") > nouns collective category 1 gaggle geese 2 dule doves 3 wake vultures Is there a known bug here or is the documentation wrong? -----Original Message----- From: R-help <r-help-boun...@r-project.org> On Behalf Of Boris Steipe Sent: Saturday, October 28, 2023 1:54 PM To: R. Mailing List <r-help@r-project.org> Subject: [R] col.names in as.data.frame() ? I have been trying to create a data frame from some structured text in a single expression. Reprex: nouns <- as.data.frame( matrix(c( "gaggle", "geese", "dule", "doves", "wake", "vultures" ), ncol = 2, byrow = TRUE), col.names = c("collective", "category") ) But ... : > str(nouns) 'data.frame': 3 obs. of 2 variables: $ V1: chr "gaggle" "dule" "wake" $ V2: chr "geese" "doves" "vultures" i.e. the col.names argument does nothing. From my reading of ?as.data.frame, my example should have worked. I know how to get the required result with colnames(), but I would like to understand why the idiom as written didn't work, and how I could have known that from the help file. Thanks! Boris ______________________________________________ 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.