how to find mean with nan

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Fani
Fani 2014년 10월 10일
댓글: Image Analyst 2014년 10월 10일
Hi!
I want to find mean with nan values and with different step. My script is:
RowDivision=[1,46,172,305,472,618,714,784,920];
nElement=diff(RowDivision); % step
meanG=cellfun(@mean,(mat2cell(G,nElement,ones(size(G,2),1)))); %mean
but if i have one only nan value i.e. from 1 to 46 the mean is nan. How can I ignore the nan? Thank you!

채택된 답변

Azzi Abdelmalek
Azzi Abdelmalek 2014년 10월 10일
편집: Azzi Abdelmalek 2014년 10월 10일
a=[1 2 nan 3 nan 10]
nanmean(a)
%or
mean(a(~isnan(a)))

추가 답변(2개)

Andrew Reibold
Andrew Reibold 2014년 10월 10일
편집: Andrew Reibold 2014년 10월 10일
Use nanmean
If you dont have it, I wrote this
For an array, x
n_nans = 0;
temp = x;
for i = 1:length(x)
if isnan(x(i))
temp(i) = 0;
n_nans = n_nans+1;
end
end
mean = sum(temp)/(length(temp)-n_nans)
  댓글 수: 1
Andrew Reibold
Andrew Reibold 2014년 10월 10일
Use Azzi's answer. Much better.

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Image Analyst
Image Analyst 2014년 10월 10일
If you have the Stats toolbox, use nanmeans. If you don't, you can do it in two lines of code, one to find the nans and one to get the mean:
% Create sample data
RowDivision=[1,46,172,305,472,618,714,784,920];
% Make some nans
RowDivision(2) = nan;
RowDivision(4) = nan
% Find the nans
nanElements = isnan(RowDivision)
% Compute the mean with no nans being considered.
meanNoNans = mean(RowDivision(~nanElements))
Actually you can do that in one line of code if you want.
  댓글 수: 1
Image Analyst
Image Analyst 2014년 10월 10일
Oops - just like Azzi's edit which he posted while I was composing my response.

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