关于集合的练习P235-1,2,3

第一题：

　　

import java.util.*;

public class ListTest {

    
    public static void main(String[] args) {
        
        ArrayList<Integer> list = new ArrayList<Integer>();
        
        for(int i=0;i<101;i++){
            
            list.add(i);
        }
        System.out.println("原先的数据：
"+list);
        
        list.remove(10);
        
        System.out.println("移除之后的数据：
"+list);
    }
}

运行的结果：

原先的数据：
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100]
移除之后的数据：
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100]

第二题：

　　

import java.util.*;

public class SetList {

    public static void main(String[] args) {
        
        ArrayList<String> list = new ArrayList<>();
        HashSet<String> set = new HashSet<String>();
        TreeSet<String> set1 = new TreeSet<String>();
        
        Collections.addAll(list, "A","a","c","C","a");
        Collections.addAll(set, "A","a","c","C","a");
        Collections.addAll(set1, "A","a","c","C","a");
        
        System.out.println("list的数据：	"+list);
        System.out.println("set的数据：	"+set);
        System.out.println("set的数据：	"+set1);
        
    }
}

运行的结果：

list的数据： [A, a, c, C, a]
set的数据： [c, A, C, a]
set的数据： [A, C, a, c]

第三题：

import java.util.*;

public class TestMap {

    public static void main(String[] args) {
        
        Emp e1 = new Emp("001","小赵");
        Emp e2 = new Emp("002","小钱");
        Emp e3 = new Emp("003","小孙");
        Emp e4 = new Emp("004","小李");
        Emp e5 = new Emp("005","小周");
        Emp e6 = new Emp("006","小吴");
        
        HashMap<String,String> m = new HashMap<String,String>();
        
        m.put(e1.getId(), e1.getName());
        m.put(e2.getId(), e2.getName());
        m.put(e3.getId(), e3.getName());
        m.put(e4.getId(), e4.getName());
        m.put(e5.getId(), e5.getName());
        m.put(e6.getId(), e6.getName());
        
        System.out.println("原始的数据：
"+m);
        
        m.remove("005");
        
        System.out.println("移除之后的数据：
"+m);
        
        
    }
}
class Emp{
    
    private String id;
    private String name;
    public Emp(String id, String name) {
        super();
        this.id = id;
        this.name = name;
    }
    public String getId() {
        return id;
    }
    public void setId(String id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    
}

运行的结果：

原始的数据：
{004=小李, 005=小周, 006=小吴, 001=小赵, 002=小钱, 003=小孙}
移除之后的数据：
{004=小李, 006=小吴, 001=小赵, 002=小钱, 003=小孙}