[R] read.table(..., header == FALSE, colClasses = <vector with names attribute>)

[Benjamin Tyner]

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.

Regards

Ben



On 10/23/2017 08:51 PM, Jeff Newmiller wrote:
> You are constructing the equivalent of a two-line data file, and complaining that it is not treating it like it was one line. If it did used to accept this silently [skeptical] then I for one am glad it produces a warning now.