Sum of the elements of rows of matrix

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Akmyrat
Akmyrat 2014-5-28
评论： Jos (10584) 2014-5-29
lets say i have A=[1 2 1;3 2 1;3 5 4] and i want to sum up row elements separately and show me results as "Ri=..." here "i" is number of row. in this case R1=7, R2=9. R3=6.
  1 个评论
Matt J
Matt J 2014-5-28
It sounds like you really mean "sum up column elements". The elements you are summing all belong to a common column, not a common row.

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采纳的回答

Matt J
Matt J 2014-5-28
编辑：Matt J 2014-5-28
Asum=sum(A,1);
for i=1:length(Asum)
disp(['R' num2str(i) '=' num2str(Asum(i))]);
end
  4 个评论
显示 2更早的评论
Matt J
Matt J 2014-5-28
Hurts in what way? As you recommended, I do not autogenerate separate variables R1, R2, R3,...
Jos (10584)
Jos (10584) 2014-5-29
:-) Indeed, you exactly did what Akmyrat asked for ...

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更多回答（2 个）

Chandrasekhar
Chandrasekhar 2014-5-28
sum(A')
  2 个评论
Matt J
Matt J 2014-5-28
编辑：Matt J 2014-5-28
This won't work if A is a row vector. Transposing is also expensive in computation time and memory if A is large.
Chandrasekhar
Chandrasekhar 2014-5-28
Please let us know what is best way to do this?

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Jos (10584)
Jos (10584) 2014-5-28
You do not want to store the results in separate variables R1, R2, etc., but rather as elements of a single variable R, with R(1), R(2), etc.
A = magic(3)
RowSum = sum(R,2)
help sum
  2 个评论
Akmyrat
Akmyrat 2014-5-28
Hi jos, thanks. but sorry your code also not working.
Jos (10584)
Jos (10584) 2014-5-28
What do you mean, "not working"? Did you read the help of sum?
May be you want to sum along rows rows, i.e., sum the elements in each column?
ColumnSum = sum(R,1)
Next time, be a little bit more specific ...

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