Question

我有2个列表

val listA = List("Mary", "Harry", "Marry", "Harry", "Marry")
val listB = List("Mary", "Harry", "Marry", "Harry", "Marry")

现在我想知道列表中所有Harry出现的索引是否相同。在scala中执行此操作的最佳方法是什么？

Answer 1

我使用迭代器只根据需要进行比较，如下所示：

def indexesOf(ls: List[String], word: String) =
  ls.iterator.zipWithIndex.collect { case (`word`, i) => i }

indexesOf(listA, "Harry") sameElements indexesOf(listB, "Harry")

Answer 2

您可以.zip列表，然后使用.exists检查是否存在一个等于"Harry"而另一个不等的元组：

scala> val listA = List("Mary", "Harry", "Marry", "Harry", "Marry")
listA: List[String] = List(Mary, Harry, Marry, Harry, Marry)

scala> val listB = List("Mary", "Harry", "Marry", "Harry", "Marry")
listB: List[String] = List(Mary, Harry, Marry, Harry, Marry)

scala> (listA zip listB).exists { case (a, b) => (a == "Harry" ^ b == "Harry") }
res5: Boolean = false

scala> val listA = List("Mary", "Harry", "Marry", "Harry", "Marry")
listA: List[String] = List(Mary, Harry, Marry, Harry, Marry)

scala> val listB = List("Mary", "Harry", "Marry", "Harry", "Harry") // changed the last one
listB: List[String] = List(Mary, Harry, Marry, Harry, Harry)

scala> (listA zip listB).exists { case (a, b) => (a == "Harry" ^ b == "Harry") }
res6: Boolean = true

比较scala列表中的元素索引

2 个答案: