Matrix to Vector every two rows

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Mark 2013-3-27

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https://ww2.mathworks.cn/matlabcentral/answers/68879-matrix-to-vector-every-two-rows

I have a matrix as follows: test2 =

         0         0
         0    0.0137
         0         0
         0    0.0081
         0         0
    0.0137    0.0081

I'd like to be able to create a single column vector from it of the form:

[0;0;0;0.0137;0;0;0;0.0081;0;0.0137;0;0.0081]

This is a structure taking each of the 2 rows of the matrix test2 and making them in column form, followed by the next two rows etc. So for the first 2x2 part of the matrix it would be row 1, column 1, followed by row 2, column 1, then row 1, column 2, and finally row 2, column 2 and so on through the matrix test2 until the end of the n x 2 matrix.

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Answer 1

Azzi Abdelmalek 2013-3-27

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https://ww2.mathworks.cn/matlabcentral/answers/68879-matrix-to-vector-every-two-rows#answer_80189

在 MATLAB Online 中打开

a=reshape(test2',2,2,[])
out=cell2mat(arrayfun(@(x) reshape(a(:,:,x)',[],1),1:size(a,3),'un',0))
out=out(:)

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Mark 2013-3-27

what is the 'un' in the arrayfun call for?

Wayne King 2013-3-27

'uniformoutput'

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Answer 2

Wayne King 2013-3-27

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https://ww2.mathworks.cn/matlabcentral/answers/68879-matrix-to-vector-every-two-rows#answer_80187

编辑：Wayne King 2013-3-27

在 MATLAB Online 中打开

B = reshape(test2',12,1);

I think you may have made a mistake in your example since the last two elements are 0 and 0.0081 and they should be 0.0137 and 0.0081.

Although I'm confused a bit by your post. In your text you say: "taking each of the 2 rows of the matrix test2 and making them in column form, followed by the next two rows etc."

but then later you talk about repeating row 1:

" So for the first 2x2 part of the matrix it would be row 1, column 1, followed by row 2, column 1, then row 1, column 2, "

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Mark 2013-3-27

编辑：Mark 2013-3-27

I want to combine it in a slightly different way actually. The two rows of column 1 followed by the two rows of column 2, then the next two rows of column 1 followed by the next two rows of column 2 and so on. so the last 4 in the matrix would be ...;0;0.0137;0;0.0081]

Mark 2013-3-27