concatenate

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God'sSon
God'sSon on 28 Mar 2011
Edited: Rajeev on 26 May 2014
I have a for-loop that executes commands and displays the answer for each iteration. Please, can someone tell me how to concatenate all the answers into an array instead of having the results displayed independently for each iteration. cheers.
  2 Comments
Rajeev
Rajeev on 26 May 2014
hey me too searching for the same question did u get the answer?
Rajeev
Rajeev on 26 May 2014
Edited: Rajeev on 26 May 2014
if u store ur answer in A. then give A as A[ ]; in array form it will store automaticly

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Accepted Answer

Walter Roberson
Walter Roberson on 28 Mar 2011
Paulo answered the question as you phrased it, but if you know the exact number of results you are producing (or if the maximum number of results is "reasonably close" to the likely number of results), then you are better off pre-allocating memory for the results:
a = zeros(10,1);
for b = 1:10
a(b) = 3*b+5; %for example
end
When you get to thousands of elements, pre-allocating can be much much faster.
  2 Comments
God'sSon
God'sSon on 28 Mar 2011
thanks for your answer.
I fancy the idea of pre-allocating memory but I couldnt implement it with my code.
consider this example:
a= 2 1 3 1
1 4 1 5
6 7 1 1
8 1 9 1
for i=(1:4)
row=(a(i,:));
b=sort(row)
end
I need an answer which is (b= 4x4 array) like the original (a)
cheers.
Walter Roberson
Walter Roberson on 28 Mar 2011
b = zeros(size(a));
for i = 1:size(a,1)
b(i,:) = sort(a(i,:))
end
Or more simply,
b = sort(a,2);

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More Answers (1)

Paulo Silva
Paulo Silva on 28 Mar 2011
a=[]
for b=1:10
a=[a b] %replace the b with the data you want to store per iteration
end
a %result is inside this variable
The code doesn't do any memory pre-allocation!!

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