how rearrange data in a matrix?

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Ved
Ved 2013-10-19
评论： Andrei Bobrov 2013-10-20
I have a data as:
data=[1 2 3 4 5 6 7 8];
I need a new data matrix (4 x 8),like this:
new_data =[ 1 2 0 0 0 0 0 0
0 0 3 4 0 0 0 0
0 0 0 0 5 6 0 0
0 0 0 0 0 0 7 8 ]
How to do it using a FOR loop ? Any help?

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采纳的回答

Azzi Abdelmalek
Azzi Abdelmalek 2013-10-19
编辑：Azzi Abdelmalek 2013-10-19
data=[1 2 3 4 5 6 7 8];
n=numel(data);
R=zeros(n/2,n);
R(:,1:2)=reshape(data,2,[])';
out=cell2mat(arrayfun(@(x) circshift(R(x+1,:),[ 0 2*x]),(0:3)','un',0))
%or
data=[1 2 3 4 5 6 7 8];
n=numel(data);
out=zeros(n/2,n);
out(sub2ind(size(out),repmat((1:n/2),2,1),reshape(1:n,2,[])))=data
%or
EDIT
n=numel(data);
a=[reshape(data,2,[]) ;zeros(n,n/2)];
a=a(:);
a(end-n+1:end)=[];
out=reshape(a,n,n/2)'
  2 个评论
Ved
Ved 2013-10-19
@Azzi: First two scripts worked perfectly.Thank you !
Ved
Ved 2013-10-19
@Azzi:
Could you please explain the line which is using cell2mat() in your first code.

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更多回答（1 个）

Andrei Bobrov
Andrei Bobrov 2013-10-19
编辑：Andrei Bobrov 2013-10-20
a = num2cell(reshape(data,1,2,[]),[1 2])
out = blkdiag(a{:});
or
out = kron(eye(4),[1 1])*diag(data);
or
out = reshape(permute(repmat(eye(4),[1,1,2]),[1 3 2]),4,[])*diag(data);
  2 个评论
Ved
Ved 2013-10-20
编辑：Ved 2013-10-20
@Andrei:
Thank You ! but third one is giving an error:
Error using repmat
Too many input arguments.
nevertheless other two options works perfectly.

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