Dear R-devel,
It appears that data.frame ignores row.names=NULL argument if it can guess the
names from the first column. This behavior seems to contradict what the help
page says, see the last sentence:
If row names are not supplied in the call to 'data.frame', the row
names are taken from the first component that has suitable names,
for example a named vector or a matrix with rownames or a data
frame. (If that component is subsequently recycled, the names are
discarded with a warning.) If 'row.names' was supplied as
'NULL'
or no suitable component was found the row names are the integer
sequence starting at one (and such row names are considered to be
'automatic', and not preserved by 'as.matrix').
Probably it should read "AND no suitable component was found ...", but
I like the promise of the original description better.
Thanks,
Vadim
> row.names(data.frame(x=c(a=1,b=2), row.names=NULL))
[1] "a" "b"> version
_
platform i386-pc-mingw32
arch i386
os mingw32
system i386, mingw32
status
major 2
minor 7.1
year 2008
month 06
day 23
svn rev 45970
language R
version.string R version 2.7.1 (2008-06-23)>
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