Scala两个列表的区别

Question

我有两个清单：

val list1 = List("word1","word2","word2","word3","word1")
val list2 = List("word1","word4")

我想从list2删除所有list1个元素，即我想要

List("word2","word2","word3") <= list1 *minus* list2

我做了list1 diff list2 这让我List("word2","word2","word3","word1")只删除了第一次出现的“word1”。

我无法将其转换为集合，因为我需要有关重复的知识（请参阅上面的“word2”）。怎么办？

Answer 1

你可以

val unwanted = list2.toSet
list1.filterNot(unwanted)

删除list2中的所有项目。 （您不需要list2中的重复知识。）

Answer 2

你可以试试这个：

val list1 = List("word1","word2","word2","word3","word1")
val list2 = List("word1","word4")

println(list1.filterNot(list2.contains(_)))

Answer 3

val list1 = List("word1","word2","word2","word3","word1")
val list2 = List("word1","word4") 
list1 diff list2

这可以做到。