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Hello everyone. How to make a matrix with unequal number of rows and columns, and make the number of rows and columns the same by adding zeros. Thank you very much.

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Wesley
Wesley on 31 May 2021
Commented: Image Analyst on 31 May 2021
How to make a matrix with unequal number of rows and columns, and make the number of rows and columns the same by adding zeros.

Accepted Answer

Rik
Rik on 31 May 2021
This isn't too difficult, as Matlab automatically fills an array with zeros as it is expanded.
S=load(websave('dataA.mat','https://www.mathworks.com/matlabcentral/answers/uploaded_files/637390/dataA.mat'));
dataA=S.dataA;size(dataA)
ans = 1×2
375 2
S=load(websave('dataB.mat','https://www.mathworks.com/matlabcentral/answers/uploaded_files/637385/dataB.mat'));
dataB=S.dataB;size(dataB)
ans = 1×2
395 2
%Store them in a cell:
c={dataA,dataB};
max_sz=max(cellfun('size',c(:).',1));
for n=find(cellfun('size',c(:).',1) < max_sz)
c{n}(max_sz,1)=0;
end
max_sz=max(cellfun('size',c(:).',2));
for n=find(cellfun('size',c(:).',2) < max_sz)
c{n}(1,max_sz)=0;
end
c
c = 1×2 cell array
{395×2 double} {395×2 double}
What you do from here is up to you.

More Answers (2)

Image Analyst
Image Analyst on 31 May 2021
Try this:
a = rand(5, 2);
% Get longest dimension.
longestDimension = length(a)
% Make rows and columns of a both be longestDimension by adding zeros:
a(longestDimension, longestDimension) = 0 % Expand shortest dimension.
whos a % Show size in command window

Mathieu NOE
Mathieu NOE on 31 May 2021
hello
see example code below
clearvars;
load('dataA.mat')
[m,n] = size(dataA);
if m>=n
out = zeros(m,m);
out(1:m,1:n) = dataA;
else
out = zeros(n,n);
out(1:m,1:n) = dataA;
end
  5 Comments
Image Analyst
Image Analyst on 31 May 2021
Ha - no Rik. Actually last time I looked there were only two Answers - yours was not there. Actually I admire people who know the cryptic ways of doing things because they're often something I cannot do or understand. It's just that often/usually I give code that looks longer because I have long descriptive variable names and lots of comments and I usually lose out to those who come along with a one liner of alphabet soup because the poster liked that it was very short. However they often come back with something like "well it works but I don't understand it so can you explain it?".

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