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.

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.

Answer 1

[Rik]

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.

Answer 2

[Image Analyst]

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

Answer 3

[Mathieu NOE]

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
    

[Image Analyst]

Evidently you've never seen the "trick" used in my answer.

[Mathieu NOE]

sorry but according to what I can see, your answer appeared after mine , I admit by only a difference of a few minutes

but I wil not fight here on this very basic question, I have other priorities

[Image Analyst]

Mine was 22 minutes ago while yours was only 17 minutes ago, but no big deal. That often happens when people are working on the question at the same time - no big deal. Just thought you and others would like to know of this trick, like I was years ago when I learned the trick from Walter. I use it often now. And of course it's always good to see alternative ways of solving the same problem. For example some people like a longer, well commented solution with longer but descriptive variable names, while others prefer to use a shorter but much more cryptic one liner like you might get with regexp(), bsxfun(), or similar functions. Anyway, have a good day. 😃

[Rik]

Is that comment about cryptic code a jab at my solution? 😉

[Image Analyst]

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?".