Hi all, I recently learned that it is possible for `as.data.frame.matrix()` to produce a data frame with 0 columns that is also entirely missing a `names` attribute, and I think this is a bug:
``` # No `names`, weird! attributes(as.data.frame(matrix(nrow = 0, ncol = 0))) #> $class #> [1] "data.frame" #> #> $row.names #> integer(0) # This is what I expected attributes(data.frame()) #> $names #> character(0) #> #> $row.names #> integer(0) #> #> $class #> [1] "data.frame" ``` In my experience, 0 column data frames should probably still have a `names` attribute, and it should be set to `character()`. Some evidence to support my theory is that OOB subsetting doesn't give the intended error with this weird data frame: ``` # Good OOB error df <- data.frame() df[1] #> Error in `[.data.frame`(df, 1): undefined columns selected # This is weird! df <- as.data.frame(matrix(nrow = 0, ncol = 0)) df[1] #> NULL #> <0 rows> (or 0-length row.names) ``` The one exception to requiring a `names` attribute that I can think of is `as.data.frame(optional = TRUE)`, mostly for internal use by `data.frame()` on each of the columns, but that doesn't seem to apply here. Thanks, Davis Vaughan ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
