Scala: How to get back the key itself when a Map does not contain it

Question

Let's assume the following Map:

val map = Map("eins" -> "one", "zwei" -> "two", "drei" -> "three")

As expected map returns the value associated with a given key:

scala> map("eins")
res0: String = one
scala> map("zwei")
res1: String = two
...

and of course it crashes if a given key does not exist:

scala> map("zehn")
java.util.NoSuchElementException: key not found: zehn

Is there a way to get back the key itself instead of an exception?

map("zehn") -> "zehn"

Thanks.

Answer 1

val map = Map("eins" -> "one", "zwei" -> "two", "drei" -> "three").withDefault(identity)