loop/cycle for producing the following sequence of numbers A={1, 4, 5, 8, 9, ....} and/or B={2, 3, 6, 7, 10,....}

Hello guys, I have two vectors: X=[0 0 0 0 0] and Y =[-1 -1 -1 -1 -1] X=[x1 x2 x3 x4 x5] and Y=[y1 y2 y3 y4 y5] i want to create a third vector which will be a combination of the elements from both vectors in the following order: Z=[-1 0 0 -1 -1 0 0 -1 -1 0] Z=[y1 x1 x2 y2 y3 x3 x4 y4 y5 x5]

I want to use for cycle for moving the index i from the first element to the last element of the vector(s), however I'm don't know how I can manipulate the i in the body of the for cycle so I can access the appropriate element of the particular vector.

For example this for cycle is separating the indices to odd ones and even ones:for i=1:10 if (mod(i,2)==1) i %odd index end if (mod(i,2)==0) i %even index end end

I would need something similar to that. It doesn't has to be for cycle.

Thanks.

Answer 1

[Thorsten]

 idx = repmat([1 1 0 0], 1, 3)
 idx = idx(2:end-1);
 X=[0 0 0 0 0], Y =[-1 -1 -1 -1 -1]
 Z(idx == 0) = X;
 Z(idx == 1) = Y;

[Guillaume]

To work wathever the size of vectors X and Y (as long as they are the same length), start with:

assert(size(X) == size(Y) && isvector(x) && mod(numel(x), 2) == 1);
idx = repmat([1 1 0 0], 1, (numel(X) + 1) / 2);

[Joseph Cheng]

if you're still wondering how to use a for loop to accomplish this then

think of the index locations of what would give you

for i =0:numel(Y)-1
   if mod(i,2)==0

end