sum all columns in a matrix

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Ariela Glikman
Ariela Glikman 2018-12-8
评论： Maneet Kaur Bagga 2022-7-5
hi,
i want to sum all the columns of some matrix.
but without using a loop or the sum function.
for ex:
for the matrix [1 3 2; 4 4 8]
i will recive [5 7 10]

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回答（2 个）

James Tursa
James Tursa 2018-12-8
Hint: Look at matrix multiplication.
Maneet Kaur Bagga
Ran in:
Hi Ariela Glikman
As per my understanding you want to get the sum of the matrix coloumn wise so you can use the MATLAB sum function. All the MATLAB functions by default work on coloumn so you get the sum directly. You can refer to the code below. Hope it helps!
x = [1 3 2; 4 4 8]
x = 2×3
1 3 2 4 4 8
sum(x)
ans = 1×3
5 7 10
  2 个评论
DGM
DGM 2022-7-5
In any practical scenario, using sum() would be perfectly sensible, but OP was working around contrived limitations -- no loops and no sum().
Maneet Kaur Bagga
Maneet Kaur Bagga 2022-7-5
Ran in:
Thanks for correcting DGM,
You can refer to the below code as a solution.
x1 = [1 2 3; 4 5 6; 7 8 9];
all =(x1);
sumcol=0;
for i=1:length(all)
sumcol = 0;
for j = 1:length(all)
sumcol = sumcol + all(j,i);
end
fprintf("%d ",sumcol);
end
12 15 18

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