find sum of the run length of non zero elements between zeros of a matrix
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suppose my matrix is
a=[ 1 2 3 0 0 0 4 5 6 0 0 0 7 8 0 0 9 0 0 ]
output wanted is
[6 15 15 9]
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채택된 답변
Walter Roberson
2021년 7월 10일
a = [ 1 2 3 0 0 0 4 5 6 0 0 0 7 8 0 0 9 0 0 ]
mask = logical(a);
starts = strfind([0 mask], [0 1]);
stops = strfind([mask 0], [1 0]) + 1;
ca = cumsum([0 a]);
ca(stops) - ca(starts)
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추가 답변 (4개)
Soniya Jain
2021년 7월 10일
a=[ 1 2 3 0 0 0 4 5 6 0 0 0 7 8 0 0 9 0 0 ];
j = 0;
i = 1;
while i ~= (length(a)+1)
if a(i)~=0
sum = 0;
while a(i)~=0
sum = sum + a(i);
i = i + 1;
end
j = j + 1;
res(j) = sum;
end
i = i + 1;
end
Here is the code of it, but if you are not familiar with how to write MATLAB code, then you can start with the MATLAB Onramp tutorial to quickly learn the essentials of MATLAB.
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Simon Chan
2021년 7월 10일
a=[ 1 2 3 0 0 0 4 5 6 0 0 0 7 8 0 0 9 0 0 ];
pos=diff(a)<0; % Position before hitting a zero
c=cumsum(a); % Cumulative sum
d=[0 c(pos)]; % Add a zero in the first position, otherwise first value will be lost
diff(d)
Image Analyst
2021년 7월 11일
Here's another way:
a = [ 1 2 3 0 0 0 4 5 6 0 0 0 7 8 0 0 9 0 0 ]
% Extract each run:
props = regionprops(logical(a), a, 'PixelValues')
% Sum up each run.
for k = 1 : length(props)
theSums(k) = sum(props(k).PixelValues)
end
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