ArrayList 去除重复元素
import java.util.*; class ArrayListDemo { public static void main(String[] args) { ArrayList arr=new ArrayList(); arr.add("java01"); arr.add("java01"); arr.add("java02"); arr.add("java03"); arr.add("java01"); arr.add("java05"); sop(arr); arr=SingleElement(arr); sop(arr); } public static ArrayList SingleElement(ArrayList al) { ArrayList newal=new ArrayList(); Iterator it=al.iterator(); while(it.hasNext()) { Object obj=it.next(); if(!newal.contains(obj)) newal.add(obj); } return newal; } public static void sop(Object obj) { System.out.println(obj); } }
去除重复的对象 除非名字和姓名不一样 才可以存入
import java.util.*; class ArrayListDemo { public static void main(String[] args) { ArrayList arr=new ArrayList(); arr.add(new person("01",22)); arr.add(new person("02",22)); arr.add(new person("01",22)); arr.add(new person("02",22)); arr.add(new person("01",22)); arr=SingleElement(arr); Iterator it=arr.iterator(); while(it.hasNext()) { person obj=(person)it.next(); System.out.println(obj.getName()+" "+obj.getAge()); } } public static ArrayList SingleElement(ArrayList al) { ArrayList newal=new ArrayList(); Iterator it=al.iterator(); while(it.hasNext()) { Object obj=it.next(); if(!newal.contains(obj)) newal.add(obj); } return newal; } public static void sop(Object obj) { System.out.println(obj); } } class person { private String name; private int age; person(String name,int age) { this.name=name; this.age=age; } public String getName() { return name; } public int getAge() { return age; } public boolean equals(Object obj) { if(!(obj instanceof person)) return false; person p=(person)obj; return this.name.equals(p.name)&&this.age==p.age; } }