Dynamically fetch value from hashmap during select spark scala

Question

I have a map defined with key value pair. While selecting column I for a dataframe I need to dynamically fetch column name as value from Map based on key provided like,

val map = HashMap("emp_id" -> "dept_id","emp_city" ->  "dept_city" );
val df1 = df.select($"$map.get($name)")

Here name will be key in map and I need to get related value in expression above but it throws error. What could be problem here

Answer 1

As suggested by Tzach, the problem was with string interpolation- changing the expression to $"df.${map.get(name).mkString}" fixed the issue

Answer 2

Just use apply:

f.select(map(name))