how to create a vector with known indices numbers

I have

vector = [1 3 4 6 7 7 8 90 8]
positions = [1 5 8]

How can I write a new_vector having the same lentgh as vector positions and containing the numbers of vector in the corresponding positions?

Answer 1

[Adam]

result = vector( positions );

will give you this, if what you mean is you want the numbers from those positions of vector rather than that you want them in those positions of the result vector too.

[Melissa Jones]

thanks!