如何从对象数组列表中找到最大元素? [英] How to find the max element from an array list of objects?

问题描述

Collections.max(arraylist) 不起作用，常规的 for 循环也不起作用.

Collections.max(arraylist) doesn't work, and a regular for loop won't work either.

我拥有的是:

ArrayList<Forecast> forecasts = current.getForecasts();

Collections.max(forecast) 给我这个错误:

The method max(Collection<? extends T>) in the type Collections is
not applicable for the arguments (ArrayList<Forecast>)

ArrayList 包含 Forecast 对象，每个对象都有一个 int 字段，用于表示每天的温度.我正在尝试将最大值存储在 int max 中.

The ArrayList holds Forecast objects which each has an int field for the temperature of each day. I am trying to store the max in an int max.

推荐答案

由于您的 ArrayList 包含 Forecast 对象，您需要定义 max 方法应该找到 ArrayList 中的最大元素.

As your ArrayList contains Forecast objects you'll need to define how the max method should find the maximum element within your ArrayList.

类似的东西应该可以工作:

something along the lines of this should work:

ArrayList<Forecast> forecasts = new ArrayList<>();
// Forecast object which has highest temperature
Forecast element = Collections.max(forecasts, Comparator.comparingInt(Forecast::getTemperature));
// retrieve the maximum temperature
int maxTemperature = element.getTemperature();

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