如何重置对象循环“计数器”？答案

【问题标题】：How do i reset Object loop "counter"?如何重置对象循环“计数器”？
【发布时间】：2021-12-09 15:48:19
【问题描述】：

如何在“if”语句为真后重新设置“city”对象并重新启动“for”语句？

private SortedSet<City> cityList;
for(City city:this.cityList)
        {
            if(city.getPopulation()==arr[i])
            {
                System.out.printf(city.getName() + "(" + city.getCountry() + ") population: " + city.getPopulation() + " area: " + city.getArea());
                i++;
            }
        }

【问题讨论】：

您使用了不同类型的循环。增强的 for 循环对您隐藏了它的迭代器，因此您无法重置它。
@azurefrog 如何将循环转换为带有 i 计数器的循环？

标签： java oop generics

【解决方案1】：

这是你想要完成的吗？

import java.util.Set;

public class City {

    public static void main(String[] args) {
        Integer[] arr = { 50_000, 100_000, 200_000 };
        Set<City> cityList = Set.of( //
                new City(100_000, "city1", "country1", "area1"), //
                new City(200_000, "city2", "country2", "area2"), //
                new City(350_000, "city3", "country3", "area3") //
        );

        outer: for (int i = 0; i < arr.length; i++) {
            for (City city : cityList) {
                if (city.getPopulation() == arr[i]) {
                    System.out.println(city.getName() + "(" + city.getCountry() + ") population: "
                            + city.getPopulation() + " area: " + city.getArea());
                    continue outer;
                }
            }
        }
    }

    private int population;
    private String name;
    private String country;
    private String area;

    public City(int population, String name, String country, String area) {
        this.population = population;
        this.name = name;
        this.country = country;
        this.area = area;
    }

    public int getPopulation() {
        return population;
    }

    public void setPopulation(int population) {
        this.population = population;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getCountry() {
        return country;
    }

    public void setCountry(String country) {
        this.country = country;
    }

    public String getArea() {
        return area;
    }

    public void setArea(String area) {
        this.area = area;
    }

}

嵌套循环时，您可以为它们添加标签 (https://www.tutorialspoint.com/break-continue-and-label-in-Java-loop)

【讨论】：

谢谢！终于工作了。
再想一想，你甚至不需要标签。您可以通过替换“继续外部”来“打破”内部循环；使用“break”并删除“outer：”标签