val digits = Set(1,7,8,0) val a= digits contains 0 System.out.println(a) val b = S

集合的操作 /用于添加或去除元素的操作符  

val digits = Set(1,7,8,0)val a= digits contains 0
  System.out.println(a)val b = Set(1,7).subsetOf(digits)System.out.println(b)val primes = Set(2,3,5,7)val u = digits union primes  u.foreach(System.out.println(_))
val u1 = digits & primes u1.foreach(System.out.println(_))
val u2 = digits -- primes u2.foreach(System.out.println(_))