如何从对象数组列表中找到max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.

我所拥有的是:

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容纳Forecast个对象，每个对象都有一个用于每天温度的int字段.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，因此您需要定义max方法应如何在ArrayList中找到最大元素.

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

类似的事情应该起作用:

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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