MATLAB: Please, correct the following logical index in vetor.

logical index

% Need to write the elements from 1 to ref, and from ref to n. Where n is the vector dimension.

X(1:ref && ref:n)

What you describe just inserts 1 element into your vector. Is that what you mean?

Anyway, this is not logical indexing. If you want to do this, you can just write

X([1:ref ref:n])

Logical indexing would be something like

X(X~=ref)

Use LOGICAL to do the type conversion:

a(logical(b))

x = (0:23).';
n = numel(x);
out = datestr([ones(n,1)*[2012 3 10] x zeros(n,2)],'HH:MM');