# Compute average of a column in a cell without considering NaN values

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Maria on 28 Jul 2014
Edited: Maria on 28 Jul 2014
I have a cell array with 3 columns and 130000 rows:
A={56276 2009 '-'
56278 2009 NaN
56281 2009 NaN
56285 2009 33.9
56301 2009 '-'
56313 2009 42.5}
I want to have the mean of the values of the third column. If I use the following code,
mean(cell2mat(A(:,3)))
I get an error because I am inlcuding 'NaN' and '-' elements to do the average and I only want to do the average of the numbers.
Can someone help me? Thanks
##### 2 CommentsShowHide 1 older comment
Maria on 28 Jul 2014
Yes I am sorry. I will edit the question

Azzi Abdelmalek on 28 Jul 2014
Edited: Azzi Abdelmalek on 28 Jul 2014
A={56276 2009 '-'
56278 2009 NaN
56281 2009 NaN
56285 2009 33.9
56313 2009 42.5}
c3=cell2mat(A(2:end,3))
out=nanmean(c3)
%or
out=mean(c3(~isnan(c3)))
##### 2 CommentsShowHide 1 older comment
Azzi Abdelmalek on 28 Jul 2014
c3=A(cellfun(@(x) ~isnan(x) & x~='-',A(:,3)),3)
out=mean(cell2mat(c3))

### More Answers (2)

Image Analyst on 28 Jul 2014
It may not be the most compact way, but it's simple and easy to understand:
clc;
A={56276 2009 '-';...
56278 2009 NaN;...
56281 2009 NaN;...
56285 2009 33.9;...
56301 2009 '-';...
56313 2009 42.5}
col3 = A(:,3)
theSum = 0;
counter = 0;
for row = 1 : size(col3, 1)
if isnumeric(col3{row}) & ~isnan(col3{row})
theSum = theSum + col3{row};
counter = counter + 1;
end
end
theMean = theSum / counter
##### 1 CommentShowHide None
Andrew Reibold on 28 Jul 2014
I'd check this answer out Maria ^

Andrew Reibold on 28 Jul 2014
Edited: Andrew Reibold on 28 Jul 2014
Hi Maria,
Here is a rough example of how to get the mean value for EVERY column gathered in your matrix. Its definitely not the best practice, but I think it will work for you.
for clmn = 1:130000
rowsum= 0;
count = 0;
for row = 1:3
if isnumeric(A{rw,clmn}) & ~isnan(A{rw,clmn})
rowsum = rowsum+ A{rw,clmn}
count= count+1
end
end
MeanOfEachColumn(clmn) = rowsum/count;
end
Now if you want the mean of column three, you can just ask for MeanOfEachColumn(3). You can do this with any column you want now.
Variable names are annoyingly long for clarity. I would play with this and let me know if you get errors
I wrote this very quickly and with minimal testing. Let me know if you find walls you can't overcome.