How to use for loop correctly and indexing my result?

a = [1 1 1 0 0 0 0 1 0 1 0 1 1 0 0 1] ;
b = [1 1 1 0 1 0 0 0 1 1 1 0 0 0 0 1] ;

S = [a, a, a, a, a, a, a, a, a ,a;b, b, b, b, b, b, b, b, b, b];

x1 = S(1:1,:);
x2 = S(2:2,:);
L = 3;
for i = 3:160
   
 x11 = [x1(i),x2(i)]
 x12 = [x1(i-1),x2(i-1)]
 x13 = [x1(i-L+1),x2(i-L+1)]
 x14 = [1]
  
 X1 = [x11 x12 x13 x14]

end

Hi this is my code. After I run it, it display the answer for x11, x12, x13, x14, and X1 directly with i = 3 to 160, a total of 158 sets of results. How to code such that i want to select my 3rd result to show only?

Answer 1

[madhan ravi]

Use ; at the end of each line inside the loop.

X1(3,:) % after the loop

[madhan ravi]

doc colon % read more about indexing

[Eric Chua]

Thanks for the follow up. Lets say i want X3 to take on the value of first iteration of the x11, x12, x13, and x14, X4 to take on the second iteration of the x11, x12, x13, and x14, and so on until X160 take on the 160th iteration of the x11, x12, x13, and x14, how to code that?

[madhan ravi]

Naming variables is a bad habit, see how much chaos it brings!

[Eric Chua]

Im still fresh to coding and im learning. Can you please help?

[madhan ravi]

Please illustrate with a short example with an expected result, so it's easy to understand the main goal.

[Eric Chua]

I have training sequence a and b with length of 16 binary element each. The S I have defined is to concatenate the sequence by itself for 10 times. So my new 'a ' will be a 1x160 matrix/row vector, and similar to b, which i have defined as x1(for new 'a') and x2(for new 'b'). For example if I concatenate the a by itself for one time,

the new a = [1 1 1 0 0 0 0 1 0 1 0 1 1 0 0 1 1 1 1 0 0 0 0 1 0 1 0 1 1 0 0 1]

From the above posted question, X1 is made up of three 1x2 vector (x11, x12, and x13) and a 1x1 vector (a noise which will remain at 1 as the last element of X1)

For example, for i = 3,

x11 = [1 1] (the first element here is from the third element of the new 'a' and second element here is from

the third element of the new 'b')

x12 = [1 1]

x13 = [1 1]

x14 = [1]

so, my X3 = [1 1 1 1 1 1 1]

For i = 4,

X11 = [0 0]

X12 = [1 1]

X13 = [1 1]

X14 = [1]

so, my X4 = [0 0 1 1 1 1 1]

Im wondering how to code this and when I want my X150 for example, I can write it in the command window and get the vector of X150.

Hope you can understand my questions, much thanks!