MATLAB: Using For Loop to find average of columns in a matrix

average columnsaverage rows

Hi I have a 4×365 matrix.
I'd like to know the average of the numbers in each column, so that's 365 values I'm looking for.
I can't use the mean() or sum() commands, and I'm trying to get this done using for loop.
X=ones(4,365)
cols=size(X,2);
for i=1:4
    for j=1:cols
        sum = sum + X(i,j);
    end
end
this gives me the final iteration. I need each iteration outputted into a new matrix so I may take the average.

Best Answer

Using a loop, without sum or mean:
X = randi(9,4,7)
N = size(X,1);
V = X(1,:);
for k = 2:N
    V = V + X(k,:);
end
And checking:
>> X
X =
   9   7   6   9   1   4   5
   5   1   5   6   2   5   8
   5   6   4   9   2   7   5
   1   6   8   4   8   5   3
>> V/N
ans =
   5.0000   5.0000   5.7500   7.0000   3.2500   5.2500   5.2500
>> mean(X,1)
ans =
   5.0000   5.0000   5.7500   7.0000   3.2500   5.2500   5.2500
Related Question