Get mean of a matrix which has NaN in it

I want to get the mean of each of the columns in a 3x4 array.

grades = [2,4,6; 5, NaN, 1; 7, 2,NaN]

The NaNs will cause the mean in that column to be a NaN so I think I have to first convert the matrix. I tried:

grades1 = cell2mat(grades)

But Matlab throws this error msg:

??? Cell contents reference from a non-cell array object.

Error in ==> cell2mat at 44

cellclass = class(c{1});

The grades matrix is a type double, so perhaps if I could convert it to something else, it would work, but when I tried a char array, it did work, but then I was still left with the NaN issue so converting it to something else appears tough.

*Note: I cannot use scripting for thiss. That means no for loops, if / else. I am just learning Matlab and I cannot use these yet.

Answer 1

[Matt J]

grades = [2,4,6; 5, NaN, 1; 7, 2,NaN]

grades = 3×3

2 4 6 5 NaN 1 7 2 NaN

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mean(grades,'omitnan')

ans = 1×3

4.6667 3.0000 3.5000

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[Project Science]

I don't think I can. I mentioned I'm using Matlab version 2008b. This gives error:

??? Subscript indices must either be real positive integers or logicals.

So 'omitnan' I don't think is supported. It doesn't show using (Reference Page Not Found)

doc omitnan

[Torsten]

Then use "nanmean":

grades = [2,4,6; 5, NaN, 1; 7, 2,NaN];
nanmean(grades,1)

ans = 1×3

4.6667 3.0000 3.5000

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[Project Science]

This worked, very simple - thanks!

[Matt J]

I am just learning Matlab ... I mentioned I'm using Matlab version 2008b.

You should really upgrade, if at all possible, or get the trial/free version of Matlab Online. It is not a very good educational exercise to learn Matlab via a 17-year old version.

Answer 2

[Torsten]

grades = [2,4,6; 5, NaN, 1; 7, 2,NaN]

grades = 3×3

2 4 6 5 NaN 1 7 2 NaN

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mean(grades,1,"omitnan")

ans = 1×3

4.6667 3.0000 3.5000

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