[R] function sum for array
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.salva...@uniroma2.it federico.belo...@uniroma2.it url: http://www.economia.uniroma2.it/phd/econometricsempiricaleconomics/ http://www.econometrics.it/ --- [[alternative HTML version deleted]] __ R-help@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.
[R] array manipulation
This worked example, hoping to be helpful, has been requested after a (my) further enquiry about array manipulation. I was looking for a command that is equivalent to repmat() in matlab and that could also be applied to array. (for Matlab users) The Matlal code was the following: temp_u=zeros(d,c,T); -creation of an array of dimensions d x c x T full of zeroes temp_u(1,:,:)=m_u;-filling the first row of each 'stratum' with the rows of the matrix 'm_u' temp_u=repmat(temp_u(1,:,:),d,1); -filling the remaining rows (full of zeroes) of 'temp_u' with copies of the corrensponding 1st row -- --- Simone Salvadei Faculty of Economics Department of Financial and Economic Studies and Quantitative Methods University of Rome Tor Vergata e-mail: simone.salva...@uniroma2.it federico.belo...@uniroma2.it url: http://www.economia.uniroma2.it/phd/econometricsempiricaleconomics/ http://www.econometrics.it/ --- [[alternative HTML version deleted]] __ R-help@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.
[R] array manipulation
This worked example, hoping to be helpful, has been requested after a (my) further enquiry about array manipulation. I was looking for a command that is equivalent to repmat() in matlab and that could also be applied to array. (for Matlab users) The Matlal code was the following: 1)temp_u=zeros(d,c,T); -creation of an array of dimensions d x c x T full of zeroes 2)temp_u(1,:,:)=m_u;-filling the first row of each 'stratum' with the rows of the matrix 'm_u' 3)temp_u=repmat(temp_u(1,:,:),d,1); -filling the remaining rows (full of zeroes) of 'temp_u' with copies of the corrensponding 1st row (what's happening if you are not a Matlab users) (numerical example d=2,c=4,T=4) 1)temp_u=zeros(d,c,T) temp_u(:,:,1) = 0 0 0 0 0 0 0 0 temp_u(:,:,2) = 0 0 0 0 0 0 0 0 temp_u(:,:,3) = 0 0 0 0 0 0 0 0 temp_u(:,:,4) = 0 0 0 0 0 0 0 0 2)temp_u(1,:,:)=m_u temp_u(:,:,1) = 0.96040.01560.02300.0009 0 0 0 0 temp_u(:,:,2) = 0.39060.29480.09810.2165 0 0 0 0 temp_u(:,:,3) = 0.53900.24820.11400.0988 0 0 0 0 temp_u(:,:,4) = 0.45460.26410.07940.2019 0 0 0 0 3)temp_u=repmat(temp_u(1,:,:),d,1) temp_u(:,:,1) = 0.96040.01560.02300.0009 0.96040.01560.02300.0009 temp_u(:,:,2) = 0.39060.29480.09810.2165 0.39060.29480.09810.2165 temp_u(:,:,3) = 0.53900.24820.11400.0988 0.53900.24820.11400.0988 temp_u(:,:,4) = 0.45460.26410.07940.2019 0.45460.26410.07940.2019 Now, in order to reply this exercise in R I used the following code: temp_u=array(0,dim=c(1,c,T)) temp_u[1,,]=m_u temp_u=kronecker(temp_u,matrix(rep(1,d),nr=d)) A special thank to David Winsemius,William Dunlap and Patrick Burns. I hope I have been helpful. --- Simone Salvadei Faculty of Economics Department of Financial and Economic Studies and Quantitative Methods University of Rome Tor Vergata e-mail: simone.salva...@uniroma2.it federico.belo...@uniroma2.it url: http://www.economia.uniroma2.it/phd/econometricsempiricaleconomics/ http://www.econometrics.it/ --- [[alternative HTML version deleted]] __ R-help@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.
[R] array manipulation
Hello,
I'm at the very beginning of the learning process of this language.
Sorry in advance for the (possible but plausible) stupidity of my question.
I would like to find a way to permute the DIMENSIONS of an array.
Something that sounds like the function permute() in matlab.
Given an array C of dimensions c x d x T , for instance, the command
permute(C, [2 1 3])
would provide (in Matlab) an array very similar to C, but this time each
one of the T matrices c x d has changed into its transposed.
Any alternatives to the following (and primitive) 'for' cycle?
*# (previously defined) phi=array with dimensions c(c,d,T)*
*
*
*temp=array(0,dim=c(c,d,T))*
* for(i in 1:T)*
* {*
* temp[,,i]=t(phi[,,i])*
* }*
* phi=temp*
*
*
Thank you very much!
S
--
---
Simone Salvadei
Faculty of Economics
Department of Financial and Economic Studies and Quantitative Methods
University of Rome Tor Vergata
e-mail: simone.salva...@uniroma2.it federico.belo...@uniroma2.it
url: http://www.economia.uniroma2.it/phd/econometricsempiricaleconomics/
http://www.econometrics.it/
---
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