Adding matrices rows having the same id

Hello, I would like to sum rows of two matrices if they have the sam id (first column). For instance, I have a matrix A and matrix B:

A = [

1 4 5 6;

2 5 5 3;

3 9 8 2];

B = [

4 5 6 2;

2 9 4 1;

1 5 7 9;

3 5 6 7;

1 4 5 3];

I would like to get matrix C such that it looks at the first column and add the other columns if id is the same in both matrices.

C = [

1 13 17 18;

2 14 9 4;

3 14 14 9;

4 5 6 2];

Thank you

[Guillaume]

When you ask a question on Answers, it's with the understanding that your question and its answer may be useful to others. Therefore we do not delete questions once they've been answered and we really don't like when the poster remove all useful content.

It's very disrepectful of the volunteers to treat us as consultants. If you want private support, Answers is not the right forum.

[Mo H]

Adam provided a great answer, and I hope it is helpful for the community

[Adam Danz]

Thanks for restoring the question and for the compliment, Mohammad.

Answer 1

[Adam Danz]

Assuming A and B have the same number of columns,

AB = [A;B]; 
C = [unique(AB(:,1)), splitapply(@(x) sum(x,1), AB(:,2:end), AB(:,1))]; 

Result:

C =
     1    13    17    18
     2    14     9     4
     3    14    14     9
     4     5     6     2

[Mo H]

thank you a lot