problems with matrix splitting

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pradeep kumar 2016-8-22

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评论： Azzi Abdelmalek 2016-8-22

Hello everyone, I want to split the matrix in such a way that when elements of 1st column are equal, the correspnding elements can be splitted into another matrix. For example, i have the following matrix.

A = [ 1 2; 1 3; 1 4; 2 1; 2 4].

i want to get the following 2 matrices as the resulting matrices.

a1 = [2;3;4] and a2= [1;4]

i have just started learning the looping in MATLAB, your coperation will be highly appreciated.

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Azzi Abdelmalek 2016-8-22

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编辑：Azzi Abdelmalek 2016-8-22

在 MATLAB Online 中打开

A = [ 1 2; 1 3; 1 4; 2 1; 2 4]
[ii,jj,kk]=unique(A(:,1),'stable')
out=accumarray(kk,A(:,2),[],@(x){x})
celldisp(out)

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pradeep kumar 2016-8-22

编辑：pradeep kumar 2016-8-22

I have no idea . So i am asking, is there any way ?

Azzi Abdelmalek 2016-8-22

I mean your question is not clear, why do you need a for loop, when accumarray can do the job?

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Stephen23 2016-8-22

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在 MATLAB Online 中打开

Use accumarray:

out = accumarray(A(:,1),A(:,2),[],@(v){v})

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pradeep kumar 2016-8-22

Thanks Stephen. That was a great help indeed. but , please note that in my actual problem A is a huge matrix of order (100 X 2). Is there anyway to use the accumarray inside a loop ? kindly help me.

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