make matrix from arrays with for loop
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Jonas K
el 23 de Jun. de 2017
Comentada: KSSV
el 23 de Jun. de 2017
Hello, I have the following problem:
array_1 = [1 2 3];
array_2 = [4 5 6];
array_3 = [7 8 9];
array_i = [.....];
I want to use a for loop to create one matrix looking like:
matrix =
1 2 3
4 5 6
7 8 9
.....
How can I realize that? Thanks, J.
3 comentarios
Stephen23
el 23 de Jun. de 2017
Editada: Stephen23
el 23 de Jun. de 2017
The most important question is: how did you get those arrays into your workspace? The best solution is to avoid creating such arrays... and luckily it is trivial to avoid when loading/importing data or when creating data. So, given that it is so trivial to avoid this problem, when not improve your code by avoiding this whole problem altogether?
About the worst solution would be to use eval (which some beginners love to use), you might like to first know what the MATLAB documentation says about it: "A frequent use of the eval function is to create sets of variables such as A1, A2, ..., An, but this approach does not use the array processing power of MATLAB and is not recommended."
You might also like to read what experienced MATLAB users say about what you are trying to do (hint: they strongly advise against it):
A much better solution is to load your data into one variable, and then simply access the data using indexing and/or fieldnames, e.g. if you use load then always load into an output variable. This will more efficient, neater, more robust, easier to check, easier to debug, faster,...
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KSSV
el 23 de Jun. de 2017
%%create arrays
array_1 = [1 2 3];
array_2 = [4 5 6];
array_3 = [7 8 9];
array_4 = [1 2 3];
array_5 = [4 5 6];
array_6 = [7 8 9];
save myfile.mat ;
clearvars
S = load('myfile.mat') ;
names = fields(S) ;
iwant = zeros(length(names),3) ;
for i = 1:length(names)
iwant(i,:) = getfield(S,names{i}) ;
end
5 comentarios
KSSV
el 23 de Jun. de 2017
Jonas, you have to follow the Stephen comments. What he said is exactly true. This practise is not good idea.
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