Summing elements of a vector without a for loop
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Given a vector/array v of length 
, I would like to create a new vector of length M where the 1st component is the sum of the 1st 5 elements of v, the 2nd element is the sum of the next 5 elements of v,... and so on until we get to the last element which is the sum of the last 5 elements of v.
, I would like to create a new vector of length M where the 1st component is the sum of the 1st 5 elements of v, the 2nd element is the sum of the next 5 elements of v,... and so on until we get to the last element which is the sum of the last 5 elements of v. Is there a quick way to do this without using a for loop?
采纳的回答
Yongjian Feng
2021-10-29
编辑：Yongjian Feng
2021-11-2
How about this:
M=3; % you know your M
v = ones(1, M^2); % your v vector
vReshaped = reshape(v, M, M)'; % Note need this.
result = sum(vReshaped, 2)';
3 个评论
Yongjian Feng
2021-11-2
Hm.. I made a mistake above. It should be this:
M = 3;
v = [1:9]
vReshaped = reshape(v, M, M)'; % need to transpose it!
result = sum(vReshaped, 2)';
n = 3;
v = 1:9; % square brackets are not required
r = sum(reshape(v,n,n),1) % transpose is not required
Yongjian Feng
2021-11-2
Cool. Even better.
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KSSV
2021-10-29
1 个投票
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