How to combine multiple nx1 size of matrix into one matrix

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As topic mentioned, i want to combine a matrix from many nx1 size matrix, i would like to have a script
Many Thnkas, Alex
  3 Comments
NG
NG on 12 Aug 2014
For example, I got matrix A, A=[1;2;3], and B, B=[4;5;6;7]. I want to combine them to be matrix C, C=[1;2;3;4;5;6;7], but now i got many matrix with differnet number of rows. How can i combine them ? Thanks!
tran thang
tran thang on 10 Oct 2015
Hi! You can reference my code! Good lucky! >> a{1} = [1 1 1;1 1 1]; >> a{1}
ans =
1 1 1
1 1 1
>> a{2} = [2 2 2;2 2 2]; >> a{3} = [3 3 3]; >> a{4} = [4 4 4;4 4 4;4 4 4]; >> a{5} = [5 5 5;5 5 5]; >> A = vertcat(a{:})
A =
1 1 1
1 1 1
2 2 2
2 2 2
3 3 3
4 4 4
4 4 4
4 4 4
5 5 5
5 5 5

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Accepted Answer

Matt J
Matt J on 12 Aug 2014
could you plz exlpain more about vertcat(matrices{:}); by showing an example.
>> matrices={[1,2;3 4],[5,6;7,8]};
>> vertcat(matrices{:})
ans =
1 2
3 4
5 6
7 8
  6 Comments
Michael Haderlein
Michael Haderlein on 12 Aug 2014
The first step to fix it is to show the code which is throwing this error ;-)

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More Answers (3)

Azzi Abdelmalek
Azzi Abdelmalek on 12 Aug 2014
Edited: Azzi Abdelmalek on 12 Aug 2014

Joakim Magnusson
Joakim Magnusson on 12 Aug 2014
Edited: Joakim Magnusson on 12 Aug 2014
Where do you have your matrices? If you can get them into cell arrays like this:
matrices = cell(1,2);
matrices{1} = A;
matrices{2} = B;
C = [];
Then you could do like this:
for i = 1:size(matrices,2)
C = [C ;cell2mat(matrices(i))]
end
I'm not sure how you want to combine your matrices but hope this was at least a little helpful.
  4 Comments
NG
NG on 12 Aug 2014
Matt , could you plz exlpain more about vertcat(matrices{:}); by showing an example. Thank You!
Michael Haderlein
Michael Haderlein on 12 Aug 2014
Thanks @Matt, I didn't use cell2mat a lot, so I didn't think about it too much. Your solution is very elegant.

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Joakim Magnusson
Joakim Magnusson on 12 Aug 2014
Edited: Joakim Magnusson on 12 Aug 2014
Sorry, i want to clarify that now i am using a loop to generate matrices out and then store them into a new matrix .Can i still use vertcat?
NG, do you mean like this?
B = [];
for i = 1:10
A = magic(4);
A(:, 2:4) = [];
B = vertcat(B, A);
end
  2 Comments
Matt J
Matt J on 12 Aug 2014
That would not be recommendable. With B growing inside the loop, you will be doing a lot of repeated memory re-allocation.

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