How to assign values to vector using linear indexing in matlab?

Question

I have a vector with NaNs:

v1 = [NaN NaN NaN NaN NaN];

another vector with different values:

v2 = [1 4 6 8 9];

and linear index:

idx = [1 0 4 0 3];

I would like to assign values in v2 to v1 according to linear index so the result would be:

v1 = [1 NaN 8 NaN 6];

Answer 1

v1(idx ~= 0) = v2(idx(idx ~= 0))

This takes

"The values in v1 where idx is not equal to zero"

and assigns them the values in

"v2, at indexes idx, where idx is also not equal to zero"