Understanding `andThen`

Question

I encountered andThen, but did not properly understand it.

To look at it further, I read the Function1.andThen docs

def andThen[A](g: (R) ⇒          


        

Answer 1

andThen is just function composition. Given a function f

val f: String => Int = s => s.length

andThen creates a new function which applies f followed by the argument function

val g: Int => Int = i => i * 2

val h = f.andThen(g)

h(x) is then g(f(x))