Store prime and non-prime numbers in two diferent vectors from a .txt

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Hi guys!
I am really new at programming with matlab, and I am stuck with one problem.
I need to read a bunch of numbers from a .txt file, determine whether this numbers are prime or not and finally store them in two diferent files.
With the code attached, what happens is that all the values from the .txt are stored in the nonprime_num vector, and I don't know why (I have tried many ways but none of them have worked).
If you could help me with this, I would be really grateful! Thank you very much!
load('Natural_numbers.txt'); %loading the data
x=Natural_numbers;
x=x'; % i want the data in a row
i=2;
prime=1;
n=length(x);
prime_num=[];
nonprime_num=[];
while i<=sqrt(x)
if rem(x,i)==0
prime=0;
break
end
i=i+1;
end
if prime==1
nonprime_num=[x, i];
else
prime_num=[x, i] ;
end

Accepted Answer

Eric Delgado
Eric Delgado on 29 Sep 2022
% x = load('Natural_numbers.txt');
x = [1, 11, 21, 23, 25, 27, 29, 30, 31, 44];
idx = isprime(x);
Prime = x(idx)
Prime = 1×4
11 23 29 31
nonPrime = x(~idx)
nonPrime = 1×6
1 21 25 27 30 44
% writematrix(Prime, "Prime.txt")
% writematrix(nonPrime, "nonPrime.txt")

More Answers (1)

David Hill
David Hill on 29 Sep 2022
Edited: David Hill on 29 Sep 2022
Attach Natural_numbers.txt is below does not work
m=readmatrix('Natural_numbers.txt');
idx=isprime(m);
nonprime_num=m(~idx);
prime_num=m(idx);

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