[R] command similar to colSums for rowSums?

Will Carr torch742 at yahoo.com
Mon Nov 30 20:01:02 CET 2009


This gives the correct result but appears to be slower than the for loop I
was using, I do appreciate the suggestion though.


Peter Ehlers wrote:
> 
> Does this
> 
>   max(apply(yourArray, 3, rowSums))
> 
> give you what you want?
> 
>   -Peter Ehlers
> 
> Will Carr wrote:
>> Working with an NxMxO sized matrix, currently I can do this in my code:
>> 
>> if (max(colSums(array)) >= number)
>> 
>> But to get an equivalent result using rowSums, I have to do:
>> 
>> for (i in 1:10)
>> {
>> if (max(rowSums(array[,,i])) >= number) 
>> }
>> 
>> I'm running both in a much larger loop that loops millions of times, so
>> speed and such is quite a big factor for me. Currently, the colSums line
>> uses about 1/10th as much time as the rowSums' for loop, and the for loop
>> actually took as much time as the rest of my code combined took to
>> execute.
>> Is there a faster way than using a for loop and rowSums?
> 
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