Question

For example, given i=5 and and n=8, I want to generate [0;0;0;0;1;0;0;0]. Specifically, I want to generate the vector v so that:

v = zeros(n,1);
v(i) = 1;

Is there a (reasonable) way to do this in one line?

Answer 1

Here’s another solution using sparse to create an n length row vector with a 1 in the ith position:

v = sparse(1,i,1,1,n)

The advantage is that for large n, this is also memory efficient and can be used as usual in matrix calculations. If you ever need the full vector, just use full.