Dealing with NaNs in a code
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Hi everyone, I'm struggling with a code that doesn't accept the NaNs. This is a part of a bigger code:
data = [y1 y2];
for i=1:5
c(:,i) = mean(data(:,i));
d(:,i)=(data(:,i));
data_demeaned(:,i) = d(:,i) - c(:,i);
end
I've tried to do this:
c(:,i) = nanmean(data(:,i));
d(:,i)= data(:,i)(~isnan(data(:,i)));/ d(:,i)=~isnan(data(:,i));
data_demeaned(:,i) = d(:,i) - c(:,i);
but it doesn't work. Any suggestion would be highly appreciated.
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回答 (1 件)
Star Strider
2017 年 4 月 7 日
I believe you’re making this more difficult than it needs to be. I do not understand what you are doing with your ‘d’ matrix, since the code doesn’t make sense, so please explain it.
Try this:
data = rand(1,30); % Create Data
data(randperm(30,10)) = NaN; % Create Data (Insert ‘NaN’ Values)
data = reshape(data, [], 5); % Create Data
c = nanmean(data);
data_demeaned = data - c;
12 件のコメント
Star Strider
2017 年 4 月 10 日
My pleasure.
That is normal, and results from numeric arrays not being defined to have ‘empty’ elements, so the matrix structure disappears and produces a vector of the ‘non-NaN’ values. (Cell arrays can have empty elements.)
You can create the original matrix as a cell array with the num2cell function. That will allow ‘empty’ elements, although it introduces the complexities of calculating with cell arrays, and does not eliminate your original problem.
That it has (Mx1) elements indicates to me that it has (M-1)*N elements that were NaN.
Since you have functions available that automatically calculate with NaN values and handle them as you want them to, I would just use those functions and not deal with eliminating the NaN values or using cell arrays.
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