CODEWITHSUNDEEP
scalascala-collections
vkt
vkt

Reputation: 1459

scala convert List(Some()) to List(string)

how to convert a scala list of some types to list of strings Ex :

List(Some(1234), Some(2345), Some(45678))
to  List("1234","2345","45678")

Upvotes: 0

Views: 1721

Answers (5)

Raman Mishra
Raman Mishra

Reputation: 2686

val str: List[String]= List(Some(123), 
Some(456), Some(789), None,
Some(234)).flatten.map(_.toString)
println(str) // will print List(123,456,789,234)

Actually flatten will ignore all the None and take some which we are mapping to string.

Upvotes: 2

stefanobaghino
stefanobaghino

Reputation: 12814

You can, as already suggested, flatten the collection and then map the toString method over its items, but you can achieve the same result in one pass by using collect:

val in = List(Some(1234), Some(2345), Some(45678))
val out = in.collect { case Some(x) => x.toString }

The collect method takes a partial function (defined with the case to destructure the Option) and applies it only to the items for which the partial function is defined (in this case, only Somes and not Nones).

You can read more about collect on the official documentation.

You can run an example and play with it here on Scastie.

Upvotes: 2

user unknown
user unknown

Reputation: 36269

Map and match:

li.map {case Some (x) => Some (s"$x")}
res103: List[Some[String]] = List(Some(1234), Some(2345), Some(45678))

Upvotes: 1

Learner
Learner

Reputation: 1190

You can go for this:

scala> List(Some(1234), Some(2345), Some(45678)).flatten.map(x => x.toString)

res11: List[String] = List(1234, 2345, 45678)

Upvotes: 4

pramesh
pramesh

Reputation: 1964

List(Some(1234), Some(2345), Some(45678)).flatten.map(_.toString)

Upvotes: 1

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