How do you append to a matrix within a for loop?

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chels19 2016-7-8

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评论： Mani 2024-5-8

Hi, I am using a for loop to process data (this part works fine). What I need to do is take the matrix (A) and after each loop update A to create one matrix. For instance, in the image below A is produced on the first loop, during loop 2 A "grows" to include the data from loop 1 and the data from loop 2, and so on.

Loop 1 produces a matrix, on the next iteration I need to append to this matrix the results of that loop, and so on until all of the data is processed.

It should be noted that the number of rows on each loop is unknown. However, the number of columns is fixed to 7.

Any ideas would be greatly appreciated please.

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采纳的回答

José-Luis 2016-7-8

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编辑：José-Luis 2016-7-8

在 MATLAB Online 中打开

 your_result = [];
 for ii = whatever
     some_vector = some_function(of_something);
     your_result = [your_result; {some_vector}];
 end

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Ruijie Zhu 2021-10-4

cheers mate

Mani 2024-5-8

Nice one.

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更多回答（2 个）

Azzi Abdelmalek 2016-7-8

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在 MATLAB Online 中打开

A=[1 2;3 4]
B=[4 5;6 7]
A=[A;B]

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chels19 2016-7-8

Thank you but this just replaces the data within the loop. I need to update A on every iteration so that it grows.

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SRIAKILAN S A 2023-2-21

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在 MATLAB Online 中打开

% make an empty array
% the main command is end+1

N=[];
for i=0:10
    x=i*i;
    N(end+1)=[x]
end
N = 0
N = 1×2
     0     1
N = 1×3
     0     1     4
N = 1×4
     0     1     4     9
N = 1×5
     0     1     4     9    16
N = 1×6
     0     1     4     9    16    25
N = 1×7
     0     1     4     9    16    25    36
N = 1×8
     0     1     4     9    16    25    36    49
N = 1×9
     0     1     4     9    16    25    36    49    64
N = 1×10
     0     1     4     9    16    25    36    49    64    81
N = 1×11
     0     1     4     9    16    25    36    49    64    81   100