How to insert a new vector to matrix in every iteration?

Hi everyone,

I try to form a matrix that gets the vector elements by using for loop. In other words, I want to save the for loop result in a matrix. You can see my code below and what I want.

for  x=1:1:3

    for y=4:1:5
        
         z = [x y]'
         ????
    end
   
end

out =

1 1 2 2 3 3

4 5 4 5 4 5

Could you help me about this 2x6 matrix, please?

Answer 1

[madhan ravi]

Trivially done without a loop:

out = [repelem(x,1:numel(x));repmat(y,1,numel(x))]

With loop:

x=1:3;
y=4:5; 
ctr=1;
out=zeros(2,numel(x)+numel(y)); % preallocate!
for  k=1:numel(x)
    for l=1:numel(y)
        out(:,ctr) = [x(k) ; y(l)];
        ctr=ctr+1;
    end
end 

Gives:

>> out

out =

     1     1     2     2     3     3
     4     5     4     5     4     5

[skinny pete]

Thank you for your answer Mr. Ravi. It works well. The purpose of the find this matrix is to plot a polygon using x and y coordinates. When I did it, I got the polygon that I do not want with several intersections due to array of the elements in the out matrix. You can see the below. So, How can I arrange of the elements' array to get smooth polygon. Do you have any idea?

 pgon = polyshape([out(1,:)], [out(2,:)]);
 plot(pgon)
 grid on

[madhan ravi]

No I don’t and I don’t see how that’s related to the question you originally asked. You'd be better off posting a new question.

[skinny pete]

ok i will ask it a new asking page

Answer 2

[Sulaymon Eshkabilov]

This one works:

x = [1   1   2    2    3    3];
y=  [4    5   4    5    4     5];
z = zeros(2, numel(x));
for  ii=1:numel(x)
        z(:,ii)=[x(ii), y(ii)];  
end

[madhan ravi]

This one works:

"Yes to a completely different question"

Learn to preallocate first!!! How does this even solve the problem??? The vertical concatenation of x and y ( which you assigned ) by the way should be the resultant of 1:3 & 4:5 , you just directly copied the result from the question and basically what your doing is

z = [x;y] % this doesn't even need a loop

You simply copied the Out's first row and assigned it as x and vice versa. Simply answering doesn't solve the problem.

[madhan ravi]

And ofcourse you're a genius :)

[madhan ravi]

I just pointed out the fault which was there and there is no need to get angry with the fact being exposed. If it’s hard just ignore else try to accept the mistake and change it.

[Sulaymon Eshkabilov]

Thanks for clarifications.