Averaging Values in a Matrix with Nans

Question

Josh 2020-5-12

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/524782-averaging-values-in-a-matrix-with-nans

评论： Josh 2020-5-12

I recently posted about something similar yesterday and thought I figured it out only to realize my output wasnt right. Im attempting to average every 2 values in a column such that a 20 x 7 matrix becomes a 10x7 matrix of averaged values. I wrote the below code with an aritrary 20 x 7 matrix as a tester however this only returns a matrix of answers that are all the same. This code below using the provided matrix for example returns a 10x7 matrix of -1's. Is there any way around this?

Edit: I kow this sample only has one "nan' value in it but future applications of this potentially have many more!

Strain=[-1,0,2,-1,-1,-1,-1;-1,1,1,1,nan,-1,-1;-1,2,2,1,-2,-2,-1;0,2,1,-1,-1,0,0;-1,1,3,-1,-2,0,-2;0,0,1,2,-1,0,-1;1,1,0,1,-1,1,-1;-1,2,1,1,-1,0,1;-2,-1,0,-1,-5,0,0;-2,1,0,1,0,0,-1;-2,1,2,1,0,-1,-1;1,1,2,0,-1,0,-2;0,3,0,2,-2,-1,-1;-2,2,1,-1,-2,0,0;-4,-1,-1,1,1,1,0;-1,2,3,1,-1,1,0;-1,1,1,1,-1,1,-1;-1,1,1,2,-1,1,0;-2,0,1,0,0,0,-1;0,2,2,1,-3,-2,-1]
endCondition=20;
for j=1:size(Strain,2)
    n=1
    for i=1:2:endCondition
        Test(n,j)=mean(Strain(~isnan(Strain(i:i+1,j))))
        n=n+1;
    end
end

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Answer 1

KSSV 2020-5-12

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链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/524782-averaging-values-in-a-matrix-with-nans#answer_431895

编辑：KSSV 2020-5-12

在 MATLAB Online 中打开

Strain=[-1,0,2,-1,-1,-1,-1;-1,1,1,1,nan,-1,-1;-1,2,2,1,-2,-2,-1;0,2,1,-1,-1,0,0;-1,1,3,-1,-2,0,-2;0,0,1,2,-1,0,-1;1,1,0,1,-1,1,-1;-1,2,1,1,-1,0,1;-2,-1,0,-1,-5,0,0;-2,1,0,1,0,0,-1;-2,1,2,1,0,-1,-1;1,1,2,0,-1,0,-2;0,3,0,2,-2,-1,-1;-2,2,1,-1,-2,0,0;-4,-1,-1,1,1,1,0;-1,2,3,1,-1,1,0;-1,1,1,1,-1,1,-1;-1,1,1,2,-1,1,0;-2,0,1,0,0,0,-1;0,2,2,1,-3,-2,-1]
M = zeros(10,7) ; 
[m,n] = size(Strain) ; 
count = 0 ; 
for i = 1:2:m
  count = count+1 ; 
  M(count,:) = nanmean(Strain(i:i+1,:)) ; 
endfor

Without loop:

Strain=[-1,0,2,-1,-1,-1,-1;-1,1,1,1,nan,-1,-1;-1,2,2,1,-2,-2,-1;0,2,1,-1,-1,0,0;-1,1,3,-1,-2,0,-2;0,0,1,2,-1,0,-1;1,1,0,1,-1,1,-1;-1,2,1,1,-1,0,1;-2,-1,0,-1,-5,0,0;-2,1,0,1,0,0,-1;-2,1,2,1,0,-1,-1;1,1,2,0,-1,0,-2;0,3,0,2,-2,-1,-1;-2,2,1,-1,-2,0,0;-4,-1,-1,1,1,1,0;-1,2,3,1,-1,1,0;-1,1,1,1,-1,1,-1;-1,1,1,2,-1,1,0;-2,0,1,0,0,0,-1;0,2,2,1,-3,-2,-1]
s = reshape(Strain',7,2,[]) ;  
s = permute(s,[2 1 3]) ; 
iwant = squeeze(nanmean(s))' ; 