I have two queries about the behaviour of drop() and apply() regarding the
dimnames and names(dimnames) of the answer. I would appreciate any
comments on this behaviour. I will submit any of this as a bug report if I
am encouraged to do so.
The first query, concerning drop(), seems to me to be a bug in ?drop, and
possibly also in the function.
?drop:
[...] Any accompanying 'dimnames' attribute is adjusted and returned with
'x'.
> x <- array(dim=c(3,2,1), dimnames=list(A=NULL, B=NULL, C=NULL))
> attributes(drop(x))
$dim
[1] 3 2
> attributes(x[,,])
$dim
[1] 3 2
I expected a dimnames attribute equivalent to list(A=NULL, B=NULL). I
think ?drop is misleading. Is the behaviour intended?
###########################################
I am less confident that the second query, concerning apply(), is a bug in
anything. But I would appreciate an explanation of the behaviour.
> x <- array(dim=c(3,2), dimnames=list(A=1:3, B=1:2))
> apply(x, 1, function(row) row)
A
1 2 3
1 NA NA NA
2 NA NA NA
> attributes(apply(x, 1, function(row) row))
$dim
[1] 2 3
$dimnames
$dimnames[[1]]
[1] "1" "2"
$dimnames$A
[1] "1" "2" "3"
What has happened to the name of the first element of the list of dimnames
of the answer? It seems arguable that if the rows of the answer are
allowed to keep their names, then the name of that dimension should also
be preserved. Should the behaviour be better documented in ?apply (which
only discusses the effect on the dim attribute AFAICS).
Thanks for any comments. Please let me know if I should submit any bug
reports concerning any of the above.
Dan
> version
_
platform i386-pc-linux-gnu
arch i386
os linux-gnu
system i386, linux-gnu
status
major 2
minor 2.0
year 2005
month 10
day 06
svn rev 35749
language R
Debian linux
[EMAIL PROTECTED]:~$ uname -a
Linux dd.princeton.edu 2.6.6 #1 SMP Fri Jul 16 13:23:04 EDT 2004 i686
GNU/Linux
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