why this error occur ??Index exceeds matrix dimensions.

i want to convert one vector(u) to two vector (u1) and (u2);

n=401;
for i=1:n
    u1(i)=u(i);
    u2(i)=u(i+n);
end

Answer 1

[KL]

You can easily access those elements just by accessing thier corresponding indices but you should make sure you accessing elements that exist.

 u = rand(1,801); %dummy data
 n=401;
 u(1:n)
 u(n+1:end)

As you see, I've used end to access until the last element. It's equivalent to writing, u(n+1:numel(u)).

Do not create extra variables and it would only make your program prone to bugs.

https://www.mathworks.com/matlabcentral/answers/304528-tutorial-why-variables-should-not-be-named-dynamically-eval

[Mohamed Eshag]

it is work now ,thanks and if I want to use for loop ,do you have any idea?

[KL]

if I want to use for loop ,do you have any idea?

What exactly are you trying to do? You probably won't even need a loop.