CODEWITHSUNDEEP
scala
Normal
Normal

Reputation: 1367

scala: list of dates to list of ranges

I've got something like this:

case class Range(start: String, end: String)
List("s1", "s2", "s3", "s4")

and I want to get:

List(Range("s1","s2"), Range("s2","s3"), Range("s3", "s4"))

For sure I can use classical java for-based solution but I looking for something more elegant.

Upvotes: 1

Views: 171

Answers (2)

Łukasz
Łukasz

Reputation: 8663

This does what you expect

list.sliding(2).collect { case List(from, to) => Range(from, to) }.toList
res0: List[Range] = List(Range(s1,s2), Range(s2,s3), Range(s3,s4))

Here is another option

(list zip list.tail) map Range.tupled

Upvotes: 2

saza
saza

Reputation: 588

Here's a simple solution that works regardless of the type of your data (which you can map to whatever you want afterwards):

scala> val l = List("s1", "s2", "s3", "s4")
l: List[String] = List(s1, s2, s3, s4)

scala> l.dropRight(1) zip l.drop(1)
res4: List[(String, String)] = List((s1,s2), (s2,s3), (s3,s4))

Cheers

Upvotes: 1

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