Replace vector of idexes with values from another vector corresponding to those indexes

I have:

a = [1 1 2 2 2 3]
b = [9 8 7]

I need :

c = [9 9 8 8 8 7]

I can do this with a loop, but I am looking for a more effecint way. I have a vector that is 1x150000 that I need to do this for.

Thank you!

Answer 1

[David Goodmanson]

Hi Nate,

c = b(a) gets it done. a becomes an index vector into the elements of b.