scala List

1、scala> val list = 1 :: 2 :: 3 :: Nil
list: List[Int] = List(1, 2, 3)

2、scala> val list = List(1,2,3)
x: List[Int] = List(1, 2, 3)

3、scala> val x = List[Number](1, 2.0, 33d, 0x1)
x: List[java.lang.Number] = List(1, 2.0, 33.0, 1)

4、scala> val x = List.range(1,10)
x: List[Int] = List(1, 2, 3, 4, 5, 6, 7, 8, 9)

5、cala> val x = List.range(0,10,2)
x: List[Int] = List(0, 2, 4, 6, 8)

6、scala> val x = List.tabulate(5)(n => n * n)
x: List[Int] = List(0, 1, 4, 9, 16)

7、// create a List
scala> val x = List(1,2,3)
x: List[Int] = List(1, 2, 3)

// prepend an element to the list
scala> val y = 0 :: x
y: List[Int] = List(0, 1, 2, 3)

a: List[Int] = List(1, 2, 3)

scala> val b = List(4,5,6)
b: List[Int] = List(4, 5, 6)

scala> val c = a ::: b
c: List[Int] = List(1, 2, 3, 4, 5, 6)

9、scala> val a = List(1,2,3)a: List[Int] = List(1, 2, 3)

scala> val b = List(4,5,6)
b: List[Int] = List(4, 5, 6)

scala> val c = List.concat(a, b)
c: List[Int] = List(1, 2, 3, 4, 5, 6)

10、scala> val x = List(1,2,3)x: List[Int] = List(1, 2, 3)

scala> x.foreach { println }
1
2
3

11、scala> var sum = 0sum: Int = 0

scala> val x = List(1,2,3)
x: List[Int] = List(1, 2, 3)

scala> x.foreach(sum += _)

scala> println(sum)
6

12、scala> val names = List("Bob", "Fred", "Joe", "Julia", "Kim")names: List[java.lang.String] = List(Bob, Fred, Joe, Julia, Kim)scala> for (name <- names if name.startsWith("J"))| println(name)JoeJulia

13、scala> val x = List(1,2,3,4,5,6,7,8,9,10)x: List[Int] = List(1, 2, 3, 4, 5, 6, 7, 8, 9, 10)// create a list of all the even numbers in the listscala> val evens = x.filter(a => a % 2 == 0)evens: List[Int] = List(2, 4, 6, 8, 10)

14、scala> val x = List(1,2,3,4,5,6,7,8,9,10)x: List[Int] = List(1, 2, 3, 4, 5, 6, 7, 8, 9, 10)scala> val y = x.takeWhile(a => a < 6)y: List[Int] = List(1, 2, 3, 4, 5)

15、scala> val x = List(1,2,3)x: List[Int] = List(1, 2, 3)scala> val y = x.map(a => a * 2)y: List[Int] = List(2, 4, 6)

16、scala> val names = List("Fred", "Joe", "Bob")names: List[java.lang.String] = List(Fred, Joe, Bob)scala> val li = names.map(name => <li>{name}</li>)li: List[scala.xml.Elem] = List(<li>Fred</li>, <li>Joe</li>, <li>Bob</li>)

17、scala> val x = List(10, 2, 5)x: List[Int] = List(10, 2, 5)scala> val y = x.sort(_ < _)warning: there were 1 deprecation warnings; re-run with -deprecation for detailsy: List[Int] = List(2, 5, 10)