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list和set的区别
更新时间: 2021-01-29 19:13:16  

1、List 是可重复集合,Set 是不可重复集合,这两个接口都实现了 Collection 父接口。List 的实现类有 ArrayList,Vector 和 LinkedList。Set 的实现类有 HashSet 和 TreeSet;

2、一个是存储单列数据的集合,另一个是存储键和值这样的双列数据的集合,List 中存储的数据是有顺序,并且允许重复;Map 中存储的数据是没有顺序的,其 key 是不能重复的,它的值是可以有重复的。

关键词: list set 区别

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