ArrayList中对象属性值的频率 [英] Frequency of object atribute value in ArrayList

问题描述

这是我的列表:

List < Game > players = new ArrayList < > ();

例如，我需要找出一种方法来计算ArrayList中包含等于"Dan"的名称的对象.

I need to find out a way to calculate how many objects in ArrayList contain a name that equals to "Dan" for example.

我在for循环中尝试了此操作，但不起作用:

I tried this in a for loop but doesn't work:

Collections.frequency(players.get( i ).name, "Dan")

推荐答案

Java 8解决方案:

Java 8 solution:

int count = players.stream()
        .filter(p -> p.name.equals("Dan"))
        .count();

Java 7解决方案:

Java 7 solution:

int count = 0;
for (Game player : players) {
    if (player.name.equals("Dan")) {
        count++;
    }
}

这篇关于ArrayList中对象属性值的频率的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！