CODEWITHSUNDEEP
scala
bharal
bharal

Reputation: 16214

Scala getting a value from a map when unsure if the map holds the value

In scala, I have a map.

I want to ask for an object - say a Train - from my map. Then I want to call the, say, "getNumberOfCarriages" method on my Train.

If I don't know if the map has an entry for the key value "Thomas", how, in scala, do I safely query for the number of carriages, or return some default value (for the sake of the example, 0?)

ie how do i call 

myMap.get("Thomas").getNumberOfCarriages()

I've seen a getOrElse method, but I am uncertain if it is applicable to the problem?

Upvotes: 0

Views: 41

Answers (1)

jwvh
jwvh

Reputation: 51271

One thing you could do is lift it to an Option and then fold over it to get either the number of carriages or a default value if None.

myMap.lift("Thomas").fold(0)(_.getNumberOfCarriages())

Upvotes: 3

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