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How to count frequency of non zero elements col wise

1 vue (au cours des 30 derniers jours)
Vishal Sharma
Vishal Sharma le 30 Juin 2017
Commenté : Stephen23 le 30 Juin 2017
I have a matrix
A = [
1 2 3 0 0;
2 2 0 2 1;
1 0 2 3 1]
I want to count column wise frequency of occurrence of all non zero numbers, i.e. 1, 2, 3 So as to get result in form of
First Col 1 (2) 2(1) 3(0)
Second Col 1(0) 2(2) 3(0)
Third Col 1(0) 2(1) 3(1)
Forth Col 1(0) 2(1) 3(1)
Fifth Col 1(2) 2(0) 3(0)

Réponse acceptée

Stephen23
Stephen23 le 30 Juin 2017
Modifié(e) : Stephen23 le 30 Juin 2017
>> [N,C] = hist(A,0:3);
>> Z = N(C~=0,:).'
Z =
2 1 0
0 2 0
0 1 1
0 1 1
2 0 0
  2 commentaires
Jan
Jan le 30 Juin 2017
Modifié(e) : Jan le 30 Juin 2017
What a pitty that hist is "not recommended" anymore. Do you knwo a method to process the matrix directly using the modern histcounts or histogram? I miss hist and histc.
But it is still working and nicer than the loop: +1
Stephen23
Stephen23 le 30 Juin 2017
@Jan Simon: as I only have access to older MATLAB versions this topic has not yet come up for me... and why they needed to be replaced is not really very clear to me either.

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Plus de réponses (1)

Jan
Jan le 30 Juin 2017
Modifié(e) : Jan le 30 Juin 2017
A = [1 2 3 0 0; ...
2 2 0 2 1; ...
1 0 2 3 1];
nCol = size(A, 2);
Edges = [unique(A(A ~= 0)); Inf];
Result = struct('N', cell(1, nCol));
for k = 1:nCol
Result(k).N = histcounts(A(:, k), Edges);
end
Or
Result = zeros(numel(Edges) - 1, nCol);
for k = 1:nCol
Result(:, k) = histcounts(A(:, k), Edges);
end

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