How to compare elements with above and below element in a column?
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Hello
I have a matrix of 4 columns. I would like to compare each element in 4th column with previous and next element in the same column. If the difference is more than 50, the elemnt should turn to 0. (This is to eliminate unexpectedly high or low values inside 4th column. Other columns should not change at all)
My written code does not work, so I will be glad if some one can help in this. I expect the result look like this:
A = [15 2 7 36
20 3 14 41
25 4 21 0
30 5 28 22]
A = [15 2 7 36
20 3 14 41
25 4 21 567
30 5 28 22]
M = length (A(:,4)),
i = A(1,4) %first element of the column
k = A(M,4) %last element of the column
for T = 2:M-1
idx = A(T,4)
if idx> 'A(T+1,4)'+200
A(idx,4) = 0;
if idx < 'A(T-1,4)'-200
A(idx,4) = 0;
end
end
fname = sprintf('new.csv');
csvwrite (fname,A); % Write to CSV file
end
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채택된 답변
James Tursa
2020년 4월 30일
Is this what you want?
for T = 2:M
if( abs(A(T,4) - A(T-1,4)) > 50 )
A(T,4) = 0;
end
end
댓글 수: 3
James Tursa
2020년 4월 30일
You need to tell us what your conditions are for the outliers, if it is not a simple test for difference > 50.
추가 답변 (1개)
Guillaume
2020년 4월 30일
Rather than coming up with your own code, I'd recommend using the filloutliers method. It doesn't have a detection method for 'more than 50 away from the two nearest neighbours' but the many detections methods are probably a lot more robust than this anyway.
A(:, 4) = filloutliers(A(:, 4), 0); %replace outliers by 0
It also has better fill methods than replacing outliers by 0.
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