What is the difference between mean(A,'omitnan') and nanmean(A) ?

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LeChat 2018-3-19

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评论： Nathan Williamson 2020-5-2

Hi, I have a vector A (or could be a matrix) which contains finite values as well as NaNs. I want to compute the mean value of its non-NaN elements. What is the difference between mean(A,'omitnan') and nanmean(A) ? Thank you!

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Answer 1

Stephen23 2018-3-19

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There is no practical difference for your vector.

Personally I would use mean, because nanmean is part of the Statistics Toolbox, so using it makes your code less portable.

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LeChat 2018-3-19

ok. It is the feeling I had. Thanks a lot!

Nathan Williamson 2020-5-2

On a related note, in my code I found median(A,'omitnan') to run significantly faster than nanmedian(A). Not sure why. In the same code, mean(A,'omitnan') and nanmean(A) have a similar runtime.

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Answer 2

Walter Roberson 2018-3-19

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nanmean() existed first, as part of the Statistics Toolbox.

Later 'omitnan' was added as an option to the regular mean() as part of basic MATLAB. nanmean() should now be used mostly for backwards compatibility.