How to count frequency of non zero elements col wise

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Vishal Sharma
Vishal Sharma 2017-6-30
评论： Stephen23 2017-6-30
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)

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采纳的回答

Stephen23
Stephen23 2017-6-30
编辑：Stephen23 2017-6-30
>> [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 个评论
Jan
Jan 2017-6-30
编辑：Jan 2017-6-30
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 2017-6-30
@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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更多回答（1 个）

Jan
Jan 2017-6-30
编辑：Jan 2017-6-30
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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