# summation of matrix in column

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Khairul Nur on 25 Nov 2019
Commented: Andrei Bobrov on 26 Nov 2019
hi, i have this final_mat (40x11), below is my code. What i trying to do is,first it will check the value of j:1 equal to j (1,2,3,4). If true, i need to sum between column in the same value of j. I tried few times but end up summation of row . and tried again until..this is my last code since fews time since morning :(
Please give me some idea how to solve this.
example of final_mat:
1 13 25 15 11 11 14 12 12 10 14
1 14 25 15 11 11 14 12 12 10 10
sum 27 50 30 22 22 28 24 24 20 24
2 13 26 14 11 11 14 12 12 13 13
2 13 25 14 12 11 14 12 12 13 13
2 13 25 14 11 11 14 12 13 13 13
3 13 24 14 11 11 14 12 12 12 14
3 13 24 14 10 11 14 12 12 13 14
for n= 1:40
for j=1:4
if final_mat(j:1)==j
for jj=2:11
sum=sum+final_mat(:,jj) % stuck here.
end
end

Andrei Bobrov on 25 Nov 2019
Edited: Andrei Bobrov on 25 Nov 2019
final_mat = [ 1 13 25 15 11 11 14 12 12 10 14
1 14 25 15 11 11 14 12 12 10 10
2 13 26 14 11 11 14 12 12 13 13
2 13 25 14 12 11 14 12 12 13 13
2 13 25 14 11 11 14 12 13 13 13
3 13 24 14 11 11 14 12 12 12 14
3 13 24 14 10 11 14 12 12 13 14];
out = varfun(@sum,array2table(final_mat),'GroupingVariables',1)
out = out{:,[1,3:end]};
or
[i,j] = ndgrid(final_mat(:,1),1:size(final_mat,2));
out = accumarray([i(:),j(:)],final_mat(:),[],@sum);
out(:,1) = unique(final_mat(:,1));
##### 2 CommentsShowHide 1 older comment
Andrei Bobrov on 26 Nov 2019
Please read about 'Name-Value Pair Argument' - 'GroupingVariable' - may be name of variable (name of column of table) or number of column of table.