How do I create and store data into a new row after every loop?
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Jaydeep Dutta
le 23 Déc 2017
Commenté : Jaydeep Dutta
le 23 Déc 2017
For example:
I am trying to update the old variable matrix but I am getting an error
f = [1 2 3 4];
a = [1 2 3 4 5 6];
old = 0;
for i = 1:length(a)
new = f.*a(i);
old(:,i) = new;
end
I want an old matrix with these values
{1 2 3 4;2 4 6 8;3 6 9 12;4 8 12 16;5 10 15 20; 6 12 18 24}
thank you
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Walter Roberson
le 23 Déc 2017
To deliberately grow the old matrix, either initialize
old = zeros(length(f),0);
or else do not initialize old at all. With what you are doing now, you are initializing old as having only one row, but then trying to write multiple rows to it.
More efficient would be to initialize the entire matrix
old = zeros(length(f), length(a));
This would not grow the matrix as you went: it would start it out as the proper size.
3 commentaires
Walter Roberson
le 23 Déc 2017
To get that error, you must be using a very old MATLAB, such as from 2009.
Try
old(:,i) = new .';
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