不用equals去List集合重复元素 - 黑马程序员技术交流社区

package com.itheima.io;
import java.util.*;
class Test
{
public static void main(String[] args)
{
ArrayList<Person> list = new ArrayList<Person>();
list.add(new Person("person1",42));
list.add(new Person("person4",23));
list.add(new Person("person3",12));
list.add(new Person("person4",23));
list.add(new Person("person2",24));
list.add(new Person("person3",12));
list.add(new Person("person1",42));
list.add(new Person("person2",24));
delete_iterator(list);
print(list);
delete_for(list);
print(list);
}
public static void print(ArrayList<Person> list)
{
for(Person p : list)
System.out.println(p);
}
public static void delete_for(ArrayList<Person> list)
{
Person pi,pj;
for(int i = 0; i<list.size();i++)
{
pi = list.get(i);//取元素
for(int j =0;j<list.size();j++)
{
pj = list.get(j);//取元素
if(j!=i)
{
if(pi.name.equals(pj.name)&&pi.age==pj.age)//如果两个相等
{
list.remove(pj);//移除pj
j--;//list长度-1,所以下一个元素往前推1位;
}
}
}
}
}
public static void delete_iterator(ArrayList<Person> list)
{
ListIterator<Person> it = list.listIterator();
while(it.hasNext())
{
Person p = it.next();
int i = 0;//移动的次数
while(it.hasNext())
{
Person p1 = it.next();
if(p.name.equals(p1.name)&&p.age==p1.age)
{
it.remove();
i--;//移除元素,相当于少移动一次;
}
i++;//向后移动了一次
}
for(;i>0;i--)//向前移动i次
it.previous();//向前移动i次,使得外层while回到原来位置;
}
}
}
class Person
{
String name;
int age;
public String toString()
{
return "name="+name+",age="+age+";";
}
Person(String name,int age)
{
this.name=name;
this.age=age;
}
}

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