Re: [Rd] [R] unvectorized option for outer()

From: Duncan Murdoch <>
Date: Tue 01 Nov 2005 - 15:56:54 GMT

On 11/1/2005 10:16 AM, Thomas Lumley wrote:

> On Tue, 1 Nov 2005, Duncan Murdoch wrote:

>> The version I posted yesterday did indeed mess up when some arguments were
>> unspecified. Here's a revision that seems to work in all the tests I can
>> think of. I also added the SIMPLIFY and USE.NAMES args from mapply to it,
>> and a sanity check to the args.
>> I did notice and work around one buglet in mapply: if you choose not to
>> vectorize any arguments, you don't get a call to the original function,
>> mapply returns "list()".
>> For example,
>>> mapply(function(x) x^2, MoreArgs = list(x=2))
>> list()
>> whereas I would think 4 is a more logical answer.
> I don't agree at all.  The answer should be the length of the longest 
> vectorised argument, and it is.

I do agree that if I'd specified something like

mapply(function(x) x^2, x=numeric(0))

then the answer (which is again list()) would be correct. But what is the length of the longest item in an empty set? I'd say it's undefined.

Duncan Murdoch mailing list Received on Wed Nov 02 03:01:25 2005

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