MATLAB: How to average column 3 when column 1 and column 2 satisfies some condition in matrix

Question

i have a n*3 matrix as shown below

A    B    C
1    1    2
1    2    22
1    2    12
1    3     0
1    3     4
2    2     6
2    2     0
2    3     2
2    3     2

I need the result as

A     B     C
1     1     2
1     2     17   # average  
1     3     4    #no need to average if value =0
2     2     6
2     3     2

Answer 1

T = readtable('file1.txt');

or

M = [1    2    22
1    2    12
1    3     0
1    3     4
2    2     6
2    2     0
2    3     2
2    3     2];
T = array2table(M,'v',{'A','B','C'});

solution:

out = varfun(@(x)sum(x)/nnz(x),T,'GroupingVariables',{'A','B'});