Question

I would like to interweave two vectors in MATLAB. In fact, I’d actually just like to add a zero between each element, but I figured I’d ask the question in such a way that I’d learn how to apply this to other situations.

My specific application:
I’d like to take a vector (e.g. [1 2 3]) and output [0 1 0 2 0 3].

The wider question:
How would I do this with two different vectors, e.g. [1 2 3] and [9 8 7] interweaving to produce [9 1 8 2 7 3].

Any help greatly appreciated, in either or both of the above questions.

Answer 1

Here’s some code that will accomplish what you want:

nums   = rand(1,3)
output = zeros(1,2*numel(nums));
output(2:2:end) = nums

The output is the following:

nums =

    0.9134    0.6324    0.0975


output =

         0    0.9134         0    0.6324         0    0.0975

Following the style of the other two answers, you could get your desired zeros output with the following:

nums = rand(1,3);
reshape([zeros(size(nums));nums],1,[])

Obviously, nums should be replaced with the vector you’d like to use. As mentioned, you should make sure it’s a row vector before calling reshape.