Apache Beam : FlatMap vs Map?

Question

I want to understand in which scenario that I should use FlatMap or Map. The documentation did not seem clear to me.

I still do not understand in which scenario I sh

Answer 1

In simplest word,

Map transformation is "one to one" mapping on each element of list/collection. Ex -

{"Amar", "Akabar", "Anthony"} -> {"Mr.Amar", "Mr.Akabar", "Mr.Anthony"}

FlatMap transformation is usually on collection like "list of list", and this collection gets flattened to single list and transformation/mapping is applied on each element of "list of list"/collection.

FlatMap transformation Ex -

{ {"Amar", "Akabar"},  "Anthony"} -> {"Mr.Amar", "Mr.Akabar", "Mr.Anthony"}

This concept remains same across programming language and across platform.

Hope it helps.