[R] data.frame() versus as.data.frame() applied to a matrix.
r@turner @end|ng |rom @uck|@nd@@c@nz
Tue Feb 5 23:22:24 CET 2019
Consider the following:
X <- matrix(runif(40),10,4)
colnames(X) <- c("a","b","a:x","b:x") # Imitating the output
# of model.matrix().
D1 <- as.data.frame(X)
D2 <- data.frame(X)
 "a" "b" "a:x" "b:x"
 "a" "b" "a.x" "b.x"
The names of D2 are syntactically valid; those of D1 are not.
Why should I have expected this phenomenon? :-)
The as.data.frame() syntax seems to me much more natural for converting
a matrix to a data frame, yet it doesn't get it quite right, sometimes,
in respect of the names.
Is there some reason that as.data.frame() does not apply make.names()?
Or was this just an oversight?
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Department of Statistics
University of Auckland
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