How to calculate the sum of each row in a matrix?
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Dear All,
I want to calculate the sum of each row in a large matrix.The matrix looks like:
y1 y2 y3 y4 y5
x2 2 4 4 6 7 Sumx2=??
x3 1 2 3 4 5 Sumx3=??
x4 1 2 3 4 5 etc
x5 1 2 4 5 6
My goal is to calculate for each x values the sum of the row. Do you have any idea to do that?
采纳的回答
Azzi Abdelmalek
2013-11-6
编辑：Azzi Abdelmalek
2013-11-6
A=[2 4 4 6 7
1 2 3 4 5
1 2 3 4 5
1 2 4 5 6]
out=sum(A,2)
2 个评论
afrya
2013-11-6
Azzi Abdelmalek
2013-11-6
编辑：Azzi Abdelmalek
2013-11-6
for example, for row 1
s=sum(A(1,:))
For row n
n=3
s=sum(A(n,:))
You have to read about array
doc array
更多回答（5 个）
Shubham Kumar
2015-5-5
6 个投票
You can create a sum matrix over rows by typing sum(matrixName, 2). This will return an array containing sum over rows.
2 个评论
James Tursa
2015-5-5
This is exactly the same answer that was already given and accepted 1 1/2 years ago.
Andrew Mccooey
2021-2-21
James Tursa. You're comment is extremely invaluable.
Delladj Kamel
2015-5-5
3 个投票
You can produce a sum vector over rows of matrix "A" by typing sum(A') where A' is the matrix transpose of matrix "A".
lurvik pokala
2021-8-8
1 个投票
how to calculate sum of all rows in a matrix given using matlab commands
loukil sana
2015-12-9
0 个投票
hi, i want to do some controle on the sum of each raw for example: y1 y2 y3 y4 y5 x2 2 4 4 6 7 Sumx2=1000 x3 1 2 3 4 5 Sumx3=1200 x4 1 2 3 4 5 Sumx4=1000 x5 1 2 4 5 6 Sumx5=1200
and i want to note that values given in the matrice are randomly genarating . thanks
Soumyabrata Bhattacharjee
2017-6-26
0 个投票
I don't know if someone has already highlighted this, I didn't go through all the answers. But coming to your question, you can try this
sum (A')'
where A is the input matrix
2 个评论
This works, but prefer sum(A, 2):
- It saves the time for transposing
- It calculates the wanted sum over the rows also if A is a coulmn matrix. Then the output must equal the input, but with sum(A')' a scalar is replied, because Matlab decides smartly to sum over the column.
Jaimie Ritchie
2022-9-21
Thank you Jan! That is very helpful. I was able to use this to just find the sum of each row with columns 2 through 4 by using sum(A(:,2:4),2).
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