Effeciently sum 3d table
On Apr 16, 2012, at 2:43 PM, David A Vavra wrote:
Thanks Petr, I'm after T1 + T2 + T3 + ...
Which would be one number ... i.e. the result you originally said you did not want.
and your solution is giving a list of n items each containing sum(T[i]). I guess I should have been clearer in stating what I need.
Or even now you _could_ be clearer. Do you want successive partial
sums? That would yield to:
Reduce("+", listoftables, accumaulate=TRUE)
Cheers, DAV -----Original Message----- From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org ] On Behalf Of Petr Savicky Sent: Monday, April 16, 2012 11:07 AM To: r-help at r-project.org Subject: Re: [R] Effeciently sum 3d table On Mon, Apr 16, 2012 at 10:28:43AM -0400, David A Vavra 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.
Hi. Use lapply(), for example listoftables <- list(array(1:8, dim=c(2, 2, 2)), array(2:9, dim=c(2, 2, 2))) lapply(listoftables, sum) [[1]] [1] 36 [[2]] [1] 44 Hope this helps. Petr Savicky.
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