本文介绍了如何检查在Java 8 Streams中是否存在任何重复?的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
在java 8中,检查列表是否包含任何重复的最佳方法是什么?我的想法是这样的:
list.size()!= list.stream()。distinct()。count()这是最好的方法吗?
解决方案你的代码需要迭代所有元素。如果你想确保没有重复的简单方法,如
public static< T> boolean containsUnique(List< T> list){ Set< T> set = new HashSet(); (t t:list) { if(!set.add(t)) return false; } 返回true; }将更有效率。
此方法也可以被重写为(假设非并行流和线程安全环境)
public static< ; T> boolean containsUnique(List< T> list){ Set< T> set = new HashSet(); return list.stream()。allMatch(t - > set.add(t)); }或作为 @ Holger 在评论中提到
public static< T> boolean containsUnique(List< T> list){ return list.stream()。allMatch(new HashSet<>():: add); }
In java 8, what's the best way to check if a List contains any duplicate?
My idea was something like:
list.size() != list.stream().distinct().count()Is it the best way?
解决方案Your code would need to iterate over all elements. If you want to make sure that there are no duplicates simple method like
public static <T> boolean containsUnique(List<T> list){ Set<T> set = new HashSet<>(); for (T t: list){ if (!set.add(t)) return false; } return true; }would be more efficient.
This method could also be rewritten as (assuming non-parallel streams and thread-safe environment)
public static <T> boolean containsUnique(List<T> list){ Set<T> set = new HashSet<>(); return list.stream().allMatch(t -> set.add(t)); }or as @Holger mentioned in comment
public static <T> boolean containsUnique(List<T> list){ return list.stream().allMatch(new HashSet<>()::add); }
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如何检查在Java 8 Streams中是否存在任何重复?
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