# Storing data from a for loop in a matrix

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CJ on 7 Apr 2016
Commented: Ced on 7 Apr 2016
Just getting started with Matlab and am running into some issues. I need to store the ouput from each step of the For Loop in a matrix. The following is my code:
% Set initial paramters.
Cl_initial=3;
R=0.5;
u=0.5;
Clt=0;
% Solve for Cl residual.
for t=[68.92 109.97 287.22 116.95 171.89 90.3 103.54];
Clt=[t; Cl_initial*(1-R)/(1-R*exp(-u*t))];
end
The way I have it set up now only saves the very last calculation in the matrix. Any help would be appreciated!

Ced on 7 Apr 2016
Edited: Ced on 7 Apr 2016
Hi
There is a search feature in the forum, you will find hundreds of examples for this.
But your problem is that you are overwriting Clt in each iteration. The solution is to save each iteration in a new column (or row). Generally speaking, it is always good to pre-initialize data containers (in this case a matrix) before filling it in a loop.
Something like:
% Set initial paramters.
Cl_initial=3;
R=0.5;
u=0.5;
t=[68.92 109.97 287.22 116.95 171.89 90.3 103.54];
Nt = length(t);
Clt = zeros(2,Nt);
% Solve for Cl residual.
for i = 1:Nt
Clt(:,i) = [ t(i) ; Cl_initial*(1-R)/(1-R*exp(-u*t(i)))];
end
##### 2 CommentsShowHide 1 older comment
Ced on 7 Apr 2016
Sure. You can "accept" the answer to close the topic if your problem was solved. Thanks!

Azzi Abdelmalek on 7 Apr 2016
Cl_initial=3;
R=0.5;
u=0.5;
Clt=[];
% Solve for Cl residual.
for t=[68.92 109.97 287.22 116.95 171.89 90.3 103.54]
Clt=[Clt;t Cl_initial*(1-R)/(1-R*exp(-u*t))]
end

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