使用不同的方法从列表中删除重复项 [英] Removing duplicates from the list with different ways
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问题描述
我有一个名为employee的类是pojo,我已经创建了这个pojo类型的员工类型的方法的列表。现在我想从列表中删除重复的,请告诉我们实现的各种方法是什么
I have an class called employee that is the pojo , and I have created the list of this pojo type means of employee type..Now I want to remove the duplicates from the list , Please advise what are the various ways to achieve that..
class Emp implements Comparable
{
String name,job;
int salary;
public Emp(String n,String j,int sal)
{
name=n;
job=j;
salary=sal;
}
public void display()
{
System.out.println(name+"\t"+job+"\t"+salary);
}
public boolean equals(Object o)
{
Emp p=(Emp)o;
return this.name.equals(p.name)&&this.job.equals(p.job) &&this.salary==p.salary;
}
public int hashCode()
{
return name.hashCode()+job.hashCode()+salary;
}
public int compareTo(Object o)
{
Emp e=(Emp)o;
return this.name.compareTo(e.name);
//return this.job.compareTo(e.job);
// return this.salary-e.salary;
}
}
类型..
import java.util.*;
class EmpListDemo
{
public static void main(String arg[])
{
ArrayList list=new ArrayList();
list.add(new Emp("Ram","Trainer",34000));
list.add(new Emp("Sachin","Programmer",24000));
list.add(new Emp("Priyanka","Manager",54000));
list.add(1,new Emp("Ravi","Administrator",44000));
list.add(new Emp("Ram","Trainer",34000));
list.add(new Emp("Anupam","Programmer",34000));
list.add(new Emp("Sachin","Programmer",24000));
list.add(new Emp("Sachin","Team Leader",54000));
System.out.println("There are "+list.size()+" elements in the list.");
System.out.println("Content of list are : ");
ListIterator itr=list.listIterator();
while(itr.hasNext())
{
Emp e=(Emp)itr.next();
e.display();
}
}
}
推荐答案
要从数组列表中删除重复的元素,您应该考虑使用一个哈希集b / c,它们不允许重复。
To remove duplicate elements from an array list you should consider using a hash set b/c they do not allow duplicates.
// Declare your reference variables
ArrayList list = new ArrayList();
HashSet hashSet = new HashSet();
// Put all list elements into hashset
hashSet.addAll(list);
list.clear();
list.addAll(hashSet);
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