To find the average when there is NaN

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I want to find the average of each pairs. ie. avg of 2 &4, avg of NaN and 5. Answer should be 3 and 5. For the second pair, code should eliminate NaN, so avg should be 5. That's where I have the problem. Following is the code I wrote. Thanks.
A=[2 4 NaN 5];
j=1;
for i=1:2:4
B=A(i:i+1);
C=~isnan(B);
test(j)=mean(A(C));
i=i+1;
j=j+1;
end

Answers (2)

Chad Greene
Chad Greene on 17 Aug 2017
Edited: Chad Greene on 17 Aug 2017
Hi Thishan,
On newer versions of Matlab, use
test(j)=mean(A(C),'omitnan');
If you have an older version of Matlab and you have the Statistics Toolbox, use
test(j)=nanmean(A(C));
Alternatively, if neither of those options work for you,
tmp = A(C);
test(j)= = mean(tmp(isfinite(tmp)));
  7 Comments
Walter Roberson
Walter Roberson on 18 Aug 2017
However, the user's for loop increments by 2, so that is not the pairs they meant. They also indicated they expected exactly 2 results, not 3.

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Image Analyst
Image Analyst on 17 Aug 2017
Edited: Image Analyst on 17 Aug 2017
This will work for any length of A, even odd numbers:
A=[2 4 NaN 5 6 8 9]; % 7 elements.
kernel = [1,1];
sumA = conv(A, kernel, 'same')
nonNaNA = ~isnan(A)
denom = conv(nonNaNA, kernel, 'same')
output = sumA ./ denom
output(isnan(output)) = [] % Remove nans.

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