How to construct this vector without loop?

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Ming
Ming 2013-10-23
编辑： Jos (10584) 2013-10-23
Hi, everyone:
I was wondering, is it possible to construct following vector without for loop?
A=[1 2 3 1 2 3 4 5 6 1 2 3 4 5 6 7 8 9 .....]
or equivalently A=[1:(3*1), 1:(3*2), 1:(3*3), 1:(3*4), ...., 1:(3*n)]
Many thanks!

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采纳的回答

Jos (10584)
Jos (10584) 2013-10-23
编辑：Jos (10584) 2013-10-23
Here is flexible version not using cell2mat:
n = 4 ; % user specified
V = 3 ; % as in the example -> [1:V 1:2*V ... 1:n*V]
ix = V*[1:n]
A = ones(1,sum(ix))
ix =ix(1:n-1)
A(cumsum(ix)+1)=-ix+1
A = cumsum(A) % result

更多回答（2 个）

Azzi Abdelmalek
Azzi Abdelmalek 2013-10-23
编辑：Azzi Abdelmalek 2013-10-23
A=[1 2 3 1 2 3 4 5 6 1 2 3 4 5 6 7 8 9]
cell2mat(arrayfun(@(x) 1:3*x,A,'un',0))
Vivek Selvam
Vivek Selvam 2013-10-23
编辑：Vivek Selvam 2013-10-23
vec = 3*(1:n);
A = cell2mat(arrayfun(@(x) 1:x,vec,'UniformOutput',0));
or
vec = 1:n;
A = cell2mat(arrayfun(@(x) 1:3*x,vec,'UniformOutput',0));

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