[R] Effeciently sum 3d table

[Bert Gunter]

Define "sum" . Do you mean you want to get a single sum for each
array? -- get marginal sums for each array? -- get a single array in
which each value is the sum of all the individual values at the
position?

Due thought and consideration for those trying to help by formulating
your query carefully and concisely vastly increases the chance of
getting a useful answer. See the posting guide -- this is a skill that
needs to be learned and the guide is quite helpful. And I must
acknowledge that it is a skill that I also have not yet mastered.

Concerning your query, I would only note that the two responses from
Greg and Petr that you received are unlikely to be significantly
faster than just using loops, since both are still essentially looping
at the interpreted level. Whether either give you what you want, I do
not know.

-- Bert

On Mon, Apr 16, 2012 at 8:53 AM, Greg Snow <538280 at gmail.com> wrote:
> Look at the Reduce function.
>
> On Mon, Apr 16, 2012 at 8:28 AM, David A Vavra <davavra at verizon.net> wrote:
>> I have a large number of 3d tables that I wish to sum
>> Is there an efficient way to do this? Or perhaps a function I can call?
>>
>> I tried using do.call("sum",listoftables) but that returns a single value.
>>
>> So far, it seems only a loop will do the job.
>>
>>
>> TIA,
>> DAV
>>
>> ______________________________________________
>> R-help at r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>
>
>
> --
> Gregory (Greg) L. Snow Ph.D.
> 538280 at gmail.com
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.



-- 

Bert Gunter
Genentech Nonclinical Biostatistics

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