java8 stream接口终端操作 count,anyMatch,allMatch,noneMatch

函数定义:

long count();  

boolean anyMatch(Predicate<? super T> predicate);  

boolean allMatch(Predicate<? super T> predicate);  

boolean noneMatch(Predicate<? super T> predicate);

anyMatch表示,判断的条件里,任意一个元素成功,返回true

allMatch表示,判断条件里的元素,所有的都是,返回true

noneMatch跟allMatch相反,判断条件里的元素,所有的都不是,返回true

例子:

List<String> strs = Arrays.asList("a", "a", "a", "a", "b");
boolean aa = strs.stream().anyMatch(str -> str.equals("a"));
boolean bb = strs.stream().allMatch(str -> str.equals("a"));
boolean cc = strs.stream().noneMatch(str -> str.equals("a"));
long count = strs.stream().filter(str -> str.equals("a")).count();
System.out.println(aa);// TRUE
System.out.println(bb);// FALSE
System.out.println(cc);// FALSE
System.out.println(count);// 4



参考: https://blog.csdn.net/qq_28410283/article/details/80783946



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posted @ 2020-02-13 17:25  yeren2046  阅读(3113)  评论(0编辑  收藏  举报