R-alpha: jpn() port
Mon, 14 Apr 1997 10:04:34 +0200
>>>>> Peter Dalgaard BSA writes:
> Kurt Hornik <Kurt.Hornik@ci.tuwien.ac.at> writes:
>> Finally, here's something that's also been on my mind for some time now
>> (and also needed help in the port). Code like
>> if(all(names(x)) == c("x", "y"))
>> fails if names(x) is NULL. Is that really necessary? (More precisely,
>> obviously we only want to test whether the two objects have equal
>> values, a la Lisp `equal').
> According to my parenthesis count, that expression will fail in any
Yes ... I meant
if(all(names(x) == c("x", "y")))
> However, I get your drift. Splus has
>  T
>  F
> Which makes sense for cases like yours. R should probably conform to
Actually, I am not sure about that, but it does not solve the problem.
If you look at the code in the S jpn package, it contains
if(all(names(region) == c("x", "y")))
If region has no names attribute,
all(names(region) == c("x", "y"))
gives NA and if(NA) (correctly) gives ``Error: Missing value where
logical needed''. The problem is that NULL == something gives NA.
(Should it really do that?)
But perhaps it is better anyway to force the programmer to check for
NULL values before comparisons ...
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