>>>>> Benjamin Tyner <bty...@gmail.com> >>>>> on Tue, 24 Oct 2017 07:21:33 -0400 writes:
> Jeff, > Thank you for your reply. The intent was to construct a minimum > reproducible example. The same warning occurs when the 'file' argument > points to a file on disk with a million lines. But you are correct, my > example was slightly malformed and in fact gives an error under R > version 3.2.2. Please allow me to try again; in older versions of R, > > read.table(file = textConnection("a\t3.14"), header = FALSE, > colClasses = c(x = "character", y = "numeric"), sep="\t") > V1 V2 > 1 a 3.14 > (with no warning). As of version 3.3.0, > > read.table(file = textConnection("a\t3.14"), header = FALSE, > colClasses = c(x = "character", y = "numeric"), sep="\t") > V1 V2 > 1 a 3.14 > Warning message: > In read.table(file = textConnection("a\t3.14"), header = FALSE, : > not all columns named in 'colClasses' exist > My intent was not to complain but rather to learn more about best > practices regarding the names attribute. which is a nice attitude, thank you. An even shorter MRE (as header=FALSE is default, and the default sep="" works, too): > tt <- read.table(textConnection("a 3.14"), colClasses = c(x="character", > y="numeric")) Warning message: In read.table(file = textConnection("a 3.14"), colClasses = c(x = "character", : not all columns named in 'colClasses' exist > If you read in the help page -- you did read that before posting, did you?--- how 'colClasses' should be specified , colClasses: character. A vector of classes to be assumed for the columns. If unnamed, recycled as necessary. If named, names are matched with unspecified values being taken to be ‘NA’. Possible values are .................. ......... and the 'x' and 'y' names you used, are matched with the colnames ... which on the other hand are "V1" and "V2" for you, and so you provoke a warning. Once you have read (and understood) the above part of the help page, it becomes, easy, no? > tt <- read.table(textConnection("a 3.14"), colClasses = > c("character","numeric")) > t2 <- read.table(textConnection("a 3.14"), > colClasses=c(x="character",y="numeric"), col.names=c("x","y")) > t2 x y 1 a 3.14 > i.e., no warning in both of these two cases. So please, please, PLEASE: at least non-beginners like you *should* take the effort to read the help page (and report if these seem incomplete or otherwise improvable)... Best, Martin Maechler ETH Zurich ______________________________________________ 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.