Question

这是我的规格说我需要做的最后一件事 // ToDo 8-遍历剩余的鱼并更改所有数据 System.out.println（“显示您的设置员正在工作：\ n”）;

我不确定该怎么做，我试图测试.set方法的链表，但令我感到困惑的是，每个元素中都有多个字段，所以我不能只写fl.add（索引，元素），我只需要知道如何更改元素的每个字段中的数据，然后可以进行另一个迭代器并进行其余操作即可。这是我的代码

Fishdata类

    public class FishData {
    private String species;  //species of fish
    private int minSize;  //min size allowed in inches
    private String season;  //fishing season
    private int limit;  //number
    private Boolean willEat;
    //constructor
    FishData(String s1, int m, String s2, int I, Boolean w){
        species = s1;
        minSize = m;
        season = s2;
        limit = I;
        willEat = w;
    }
    public String toString(){
        return species + "" + minSize + "" + season + "" + limit + "" + willEat;
    }
    public String getSpecies(){
        return this.species;
    }
    public String getSeason(){
        return this.season;
    }
    public Boolean getWillEat(){
        return this.willEat;
    }
    public int getminSize() {
        return this.minSize;
    }
    public int getLimit() {
        return this.limit;
    }


    public void setSpecies(String species) {
        this.species = species;
    }
    public void setSeason(String season) {
        this.season = season;
    }
    public void setWillEat(Boolean willEat) {
        this.willEat = willEat;
    }
    public void setminSize(int minSize) {
        this.minSize = minSize;
    }
    public void setlimit(int limit) {
        this.limit = limit;
    }

}

主班

import java.util.Collections;
import java.util.LinkedList;
import java.util.Iterator;
public class GoneFishin {
    public static void main(String[] args) {
        //create linked list of fish data called fl
        LinkedList<FishData> fl = new LinkedList<FishData>();
        //Here are a few data items
        fl.add(new FishData("American Eel ", 9, "Summer/Spring ", 25, false));
        fl.add(new FishData("Hammerhead Shark ", 0, "All Year ", 36, false));
        fl.add(new FishData("Horseshoe Crab ", 7, "All Year except May ", 60, false));
        fl.add(new FishData("Haddock ", 18, "All Year ", 0, true));
        fl.add(new FishData("Tautog ", 16, "late Spring to end of year ", 3, true));

        for (FishData element : fl) {
            System.out.println(element);
        }
        System.out.print("SIZE OF LISTt: ");
        System.out.println(fl.size());

        System.out.print("SECOND ELEMENT IN LIST: ");
        System.out.println(fl.get(1));

        System.out.print("LAST ELEMENT IN LIST: ");
        System.out.println(fl.getLast());

        Iterator<FishData> itr2 = fl.iterator();

        System.out.println("PRINTING ALL ELEMENTS USING ITERATOR");
        while (itr2.hasNext()) {
            System.out.println(itr2.next());
        }
        Iterator<FishData> itr = fl.iterator();
        while (itr.hasNext()) {
            FishData b = (FishData) itr.next();
            if (b.getWillEat()== false) {
                itr.remove();
            }
        }
        System.out.println("FISH THAT ARE GOOD TO EAT");
        for (FishData element : fl) {
            System.out.println(element);
        }
     fl.set(1,"Shrekfish", 19, "whenever it wants", 7, false);


 }
}

我知道最后的fl.set无法正常工作，给我一个错误，我只是想弄清楚它是如何工作的，所以我正在测试它。

Answer 1

您需要将其更改为

fl.set(1, new FishData("Shrekfish", 19, "whenever it wants", 7, false));

*如果我正确理解了您的问题。这会将索引1处的元素替换为新的对象

如果您只想更新单个元素，则

for (FishData element : fl) {
    element.setminSize (28);  // or whatever
    System.out.println(element);
}

Answer 2

在fl（这是一个链接列表）中，通过删除某些鱼来进行缩减之后，似乎任务是迭代所有剩余的鱼，并在其上调用设置器。因此，类似：

for (FishData element : fl) {
  element.setSeason("Winter, Summer, Spring, or Fall");
}

如果我理解这个问题，我们的想法是更新每个剩余元素的值。

使用迭代器更改链接列表中的特定字段

2 个答案: