Scala tuple与map

一 tuple

1. scala>(1,2)
2. res27:(Int,Int)=(1,2)
4. scala>(1->2)
5. res28:(Int,Int)=(1,2)
7. scala>(1,"Alice","Math",97.5)
8. res30:(Int,String,String,Double)=(1,Alice,Math,97.5)
10. scala> val t =(1,"Alice","Math",97.5)
11. t:(Int,String,String,Double)=(1,Alice,Math,97.5)
13. scala> t._1
14. res31:Int=1
16. scala> t._2
17. res32:String=Alice
19. scala> t._3
20. res33:String=Math
22. scala> t._4
23. res34:Double=97.5
25. scala> l
26. res35:List[Int]=List(1,2,3)
28. scala>def sumSq(in:List[Int]):(Int,Int,Int)=
29. |in.foldLeft((0,0,0))((t,v)=>(t._1+1,t._2+v,t._3+v*v))
30. sumSq:(in:List[Int])(Int,Int,Int)
32. scala> sumSq(l)
33. res36:(Int,Int,Int)=(3,6,14)

二 Map[K,V]

1. scala> val p =Map(1->"Davie",2->"Elwood")
2. p: scala.collection.immutable.Map[Int,String]=Map(1->Davie,2->Elwood)
4. scala> p(1)
5. res37:String=Davie
7. scala> p(2)
8. res38:String=Elwood
10. scala> p.contains(1)
11. res39:Boolean= true
13. scala> p.contains(3)
14. res40:Boolean= false
16. scala> p.keys
17. res41:Iterable[Int]=Set(1,2)
19. scala> p.values
20. res42:Iterable[String]=MapLike.DefaultValuesI