help counting number of times a value occurs across matrix

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Kitt
Kitt 2024-11-4，21:00
编辑： Bruno Luong 2024-11-5，9:30
I have an 19x100 matrix, dp, that can have a variety of values in it
111, 112, 121, 122, 211, 212, 221, 222, 311, 312, 321, 322, 411, 412, 421, 422
I want to count the number of times each value occurs in the matrix, thus, the number for each count should never be more than 100 and the sum of all the counts across each row should be 100
I've tried using the sum function but that doesn't seem to be working with the way I have it set up
count_111 = sum(dp == 111,2);
I thought this would sum up the number of times 111 occurs across each row but it's summing 111 with all the 111
Which function should I use to just count the number of times each value occurs?
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Kitt
Kitt 2024-11-4，22:14
Yeah, this matrix wasn't intially meant to be created, it was made very early on to try and identify a problem, so I didn't premake it and fill it with zeros, it was just thrown into the for loop. That has now been fixed.

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回答（2 个）

Matt J
Matt J 2024-11-4，22:34
Ran in:
values = [111, 112, 121, 122, 211, 212, 221, 222, 311, 312, 321, 322, 411, 412, 421, 422];
edges=[values,inf];
dp = [111 112 121 111 211; 111 111 321 411 111]
dp = 2×5
111 112 121 111 211 111 111 321 411 111
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for i=1:height(dp)
counts(i,:)=histcounts(dp(i,:),edges);
end
counts
counts = 2×16
2 1 1 0 1 0 0 0 0 0 0 0 0 0 0 0 3 0 0 0 0 0 0 0 0 0 1 0 1 0 0 0
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Bruno Luong
Bruno Luong 2024-11-5，8:06
编辑：Bruno Luong 2024-11-5，9:30
Ran in:
Alternative way of counting
% Random test array
A = round(10 + 2 * randn(3,10))
A = 3×10
10 12 11 11 9 10 8 11 14 9 12 12 12 12 11 13 12 9 8 9 10 5 11 7 11 11 9 10 11 9
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% Count #repetitions by row
[value,~,J] = unique(A);
[m,n] = size(A);
I = repmat(1:m,1,n);
C = accumarray([I(:),J],1);
% Make nice output
Counts = num2cell(C.',1);
Varnames = sprintfc('CountRow%d', 1:m);
CountTable = table(value, Counts{:}, VariableNames = ['Value', Varnames])
CountTable = 9x4 table
Value CountRow1 CountRow2 CountRow3 _____ _________ _________ _________ 5 0 0 1 7 0 0 1 8 1 1 0 9 2 2 2 10 2 0 2 11 3 1 4 12 1 5 0 13 0 1 0 14 1 0 0

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