MATLAB Answers

how to find rows and columns without using size

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Hanwool Yun
Hanwool Yun on 14 Sep 2019
Commented: Adam Danz on 15 Sep 2019
Introductory MATLAB course, haven't covered loops and such yet. I'm curious how to find rows + columns of an array without using size fxn? Obv numel()/length() give you rows + columns, but they don't tell you which is which. What to do next?

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Guillaume
Guillaume on 15 Sep 2019
What is the actual text of the assignment, not your interpretation of it?
An assignment that asks you to find the size of a matrix without using the size function would be completely absurd. Sure you can find all sorts of roundabout ways of doing it, none of which would teach you anything useful and all of them requiring more advanced knowledge than the size function.

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Answers (2)

Bruno Luong
Bruno Luong on 14 Sep 2019
Edited: Bruno Luong on 14 Sep 2019
for 2D array
p=numel(A);
if p==0
try
r = A(1,:);
n = 0;
m = numel(A*zeros(0,1));
catch
m = 0;
m = numel(zeros(1,0)*A);
end
else
m = numel(A(:,1));
n = p/m;
end

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Hanwool Yun
Hanwool Yun on 14 Sep 2019
unfortunately we haven't covered loops yet, is there any way to do this with basics, like using length and numel and indexing?

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Bruno Luong
Bruno Luong on 15 Sep 2019
[numel(prod(A,2)) numel(prod(A,1))] % prod instead of sum for a change

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