Re: [R] apply and arrays

From: Prof Brian Ripley <ripley_at_stats.ox.ac.uk>
Date: Mon 25 Jul 2005 - 16:58:53 EST

On Mon, 25 Jul 2005, Uwe Ligges wrote:

> Laura Holt wrote:
>
>> Hi R!
>>
>> I have a 3 dimensional array, which is 21 x 3 x 3
>>
>> I want to use apply to sum on each 21x3 matrix, which is fine.
>>
>> Is there a way that I can do this in 1 step instead of a loop (3), please?
>
> Don't know which direction you mean, I guess one of the following:
>
> apply(x, c(1,2), sum)
> apply(x, 3, sum)

Or use rowSums or colSums for clarity (and speed, irrelevant here).

-- 
Brian D. Ripley,                  ripley@stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595

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Received on Mon Jul 25 17:04:01 2005

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