How to apply a function to each element of an array column in Postgres?

Question

A Pg query returns an array. I would like to retrieve that with each element formatted to 3 decimal places. How can I apply a function to each element of an array? Something

Answer 1

postgres=# select array(select round(unnest(array[1.2,2.4,3,4])));
   array   
-----------
{1,2,3,4}
(1 row)