Ranges (Scala 3 Video)
Whenever you do these things, you’re using the Scala Range data type:
// Range in a `for` expression
val xs = for i <- 1 to 3 yield i * 10
// converting a Range to a List or Vector
(1 to 10).toList
(1 to 10).toVector
// other Ranges
1 to 5
0 to 10 by 2
0 to 100 by 10
Can use until as well as to:
(1 to 5).toList // List(1, 2, 3, 4, 5)
(1 until 5).toList // List(1, 2, 3, 4)
Can use Char values in ranges:
val r = ('a' to 'f').toList // List(a, b, c, d, e, f)
val r = ('a' to 'f' by 2).toList // List(a, c, e)
Infix methods
In uses like this, Range is used as a Scala infix method:
1 to 3
These two are equivalent:
1 to 3
1.to(3)
Laziness
Ranges are lazy:
val r = 1 to Int.MaxValue // nothing happens right away
// these are all lazy
r.take(1)
r.drop(1)
r.distinct
r.tail
// this forces the action
r.filter(_ > 100)
r.map(_ * 2)
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