how to find mean with nan

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!

Answer 1

[Azzi Abdelmalek]

a=[1 2 nan 3  nan 10]
nanmean(a)

%or

mean(a(~isnan(a)))

Answer 2

[Andrew Reibold]

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)

[Andrew Reibold]

Use Azzi's answer. Much better.

Answer 3

[Image Analyst]

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.

[Image Analyst]

Oops - just like Azzi's edit which he posted while I was composing my response.