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how to store vectors into matrix

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amina amzgh
amina amzgh on 19 Aug 2020
Answered: Image Analyst on 20 Aug 2020
I have a vector which takes different values ​​at each iteration I would like to store the result of the vectors in a matrix example iteration 1 A = [1 2 3 4] iteration 2 A = [5 6 7 8] so I will want a result matrix: result = [1 2 3 4; 5 6 7 8]

Answers (5)

KSSV
KSSV on 19 Aug 2020
m = 10 ; n = 4 ;
A = zeros(m,n) ;
for i = 1:m
A(i,:) = rand(1,n) ;
end

David Hill
David Hill on 19 Aug 2020
for k=1:100
A(k,:)=randi(100,1,4);%your vectors
end

Image Analyst
Image Analyst on 19 Aug 2020
Try this:
result = zeros(numIterations, 4);
for k = 1 : numIterations
% Get A somehow, then
result(k, :) = A;
end

Ruger28
Ruger28 on 19 Aug 2020
Edited: Ruger28 on 19 Aug 2020
A = [1 2 3 4];
B = [5 6 7 8];
C = [A;B]
In a loop:
Sum_Matrix = []; % pre-allocate if you know how many total elements in array you'll have
A = [1 2 3 4];
for ii = 1:100 % number of iterations
% whatever math to get you your vector
B = A * ii; % example
Sum_Matrix = [Sum_Matrix;B];
end
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Image Analyst
Image Analyst on 20 Aug 2020
If the "A" is really as predictable as you implied in your comment to Ruger28 (and not general as I assumed in my Answer), and you want a vectorized way to do it, you can use reshape:
numIterations = 5; % Whatever you want/need.
result = reshape([1 : numIterations*4]', 4, [])'
You get:
result =
1 2 3 4
5 6 7 8
9 10 11 12
13 14 15 16
17 18 19 20
Of course, this vectorized version is the more MATLAB-y way to do it. No for loops are needed at all. (This way also uses your preferred and better variable name of "result".)

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