Java:列表中元素的数量 [英] Java: count of elements in a list

问题描述

可能重复:
如何计算列表中元素的出现

我有一个类似List<String> A={12, 12, 14, 16, 16}的列表.我怎样才能清楚地找到元素的数量

12->2
14->1
16->2

通过使用countElements(A,"12")或A.count("12")之类的功能来

?是否有库或函数?

解决方案

您还可以使用方法How to count occurrence of an element in a List

I have a list like List<String> A={12, 12, 14, 16, 16}. How can I find the number of elements distinctly as

12->2
14->1
16->2

by using a function like countElements(A,"12") or A.count("12")? Is there a library or a function?

解决方案

You can also utililize the method Collections.frequency if you need the frequency of only some of the elements individually.

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