MATLAB: Combining vectors of different lengths alternatively.

Question

I'm trying to combine two vectors, using one element from each per step.

Say A = [1,3,5] and B = [ 2,4]

I would like to combine them to C =[1,2,3,4,5]

Vectors A and B can either be equal of length or differ by maximum of 1.

One can also be empty and the other of size 1.

I have tried various solutions I found online but Mathlab throws "Error using vertcat/horzcar", since sometimes the vectors differ in length.

Thanks in advance!

Answer 1

Try this

clear C
A = [7 2 3];
B = [1 4];
na = numel(A);
nb = numel(B);
if na > nb
    C([1:2:na*2-1 2:2:nb*2]) = [A B];
else
    C([2:2:na*2 1:2:nb*2-1]) = [A B];
end

Result:

C =
     7     1     2     4     3

The following one-liner is a bit cryptic but works correct

clear C
A = [7 2 3];
B = [1 4];
na = numel(A);
nb = numel(B);
C([1+(na<nb):2:na*2-(na>nb) 1+(nb<na):2:nb*2-(nb>na)]) = [A B];

Note: If the number of elements in B is higher then A, then the resulting vector C starts with the first element of B.