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function sum for array
2 messages · Simone Salvadei, R. Michael Weylandt
It might not be as general as you have in mind, but this works: X = array(1:24, c(2,3,4)) rowSums(X, dims = 2) Combined with aperm() it's pretty powerful. Michael On Thu, Nov 17, 2011 at 11:24 AM, Simone Salvadei
<simone.salvadei at gmail.com> wrote:
I'm looking for a function that allows to sum the elements of an array along a dimension that can be different from the classical ones (rows or columns). Let's suppose for example that: - A is an array with dimensions 2 x 3 x 4 - I want to compute B, a 2 x 3 matrix with elements equal to the sum of the corrensponding elements on each of the 3 strata. I've tried to use ? apply(A,3,sum) but the result is a vector, not a matrix. Another solution is a less elegant B=matrix(rep(0,6),ncol=3) for(t in 1:4) B = B + A[ , , t] May anybody help? S -- ------------------------------------------------------------------- Simone Salvadei Faculty of Economics Department of Financial and Economic Studies and Quantitative Methods University of Rome Tor Vergata e-mail: simone.salvadei at uniroma2.it <federico.belotti at uniroma2.it> url: http://www.economia.uniroma2.it/phd/econometricsempiricaleconomics/ <http://www.econometrics.it/> ------------------------------------------------------------------- ? ? ? ?[[alternative HTML version deleted]]
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