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How can I save data from for loop?

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majid
majid on 13 Apr 2024
Answered: Vaibhav on 25 Jul 2024 at 5:56
Hello.
I have 3 arrays of scalar number. I want to have some simple calculation on all numbers of these 3 arrays one by one (Permutation of all arrays numbers ), then multiplying every result (y) with rand(4,20) and finally saving every result as a excel data. I wrote the below codes but I have some problem: "I see in the output only the last multipication result of y" and therefore just last w.
clc
clear all
i=0;
j=1;
n=1;
A = [10 20 30 40 50 10];
B = [1 1.2 1.4 1.6 1.8 1];
C = [5 25 45 65 85 5];
z= rand(4,20);
for a = 1:125
i=i+1;
if i==6
j=j+1;
i=1;
end
if j==6
n=n+1;
j=1;
end
if(n==6)
n=1;
break ;
end
A_2 = A(i);
B_2 = B(j);
C_2 = C(n);
y = A_2 * B_2 * C_2 - A_2 * C_2;
w = y * z;
end
  2 Comments
Dyuman Joshi
Dyuman Joshi on 13 Apr 2024
"I see in the output only the last multipication result of y" and therefore just last w."
Preallocate w and use indexing (i.e. loop variable a) to save the values in it.
majid
majid on 13 Apr 2024
thankyou for your answeing.

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Answers (1)

Vaibhav
Vaibhav on 25 Jul 2024 at 5:56
Hi Majid
Code is overwriting the variable w in each iteration of the loop, so only the result from the last iteration is saved. To store all the results, you can save each w in a cell array or a 3D matrix. Below is a modified version of your code that saves each result in a cell array.
clc;
clear all;
i = 0;
j = 1;
n = 1;
A = [10 20 30 40 50 10];
B = [1 1.2 1.4 1.6 1.8 1];
C = [5 25 45 65 85 5];
z = rand(4,20);
% Initialize cell array to store results
results = cell(125, 1);
for a = 1:125
i = i + 1;
if i == 6
j = j + 1;
i = 1;
end
if j == 6
n = n + 1;
j = 1;
end
if n == 6
n = 1;
break;
end
A_2 = A(i);
B_2 = B(j);
C_2 = C(n);
y = A_2 * B_2 * C_2 - A_2 * C_2;
w = y * z;
% Store the result in the cell array
results{a} = w;
end

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