How to take the average of each column of a matrix without including a certain number

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I have a matrix that has 864 rows and 7 columns and is filled with positive numbers and zeros. I want to take the average of each of those columns. However when MATLAB is taking the averages, I dont want it to include the zeros in its calculations. Can this be done?

Respuesta aceptada

Joseph Cheng
Joseph Cheng el 16 de Jul. de 2014
What you can do is do a quick substitution. if you know your matrix doesn't have any NaN (Not a number) then substitute the 0's for nan and then use the nanmean() which will exclude the NaNs from the average.
NonZeroAverages = nanmean(B);

Más respuestas (2)

Image Analyst
Image Analyst el 16 de Jul. de 2014
If you don't have nanmean because you don't have the Finance or Statistics toolbox, you can simply do
columnMeans = sum(a, 1) ./ sum(a~=0);
where "a" is the name of your matrix. This sums up the values in each column, then divides it by the sum of the non-zero values in each column.

Sara el 16 de Jul. de 2014
Let's call your array "a":
my_mean = zeros(size(a,2),1);
for i = 1:size(a,2)
d = a(:,i);d = d(d~=0);
my_mean(i) = mean(d);


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