在Java中删除TreeMap的第一个条目
要删除TreeMap的第一个条目，请使用pollFirstEntry()方法。
让我们首先创建一个TreeMap并添加元素-
TreeMap<Integer,String> m = new TreeMap<Integer,String>(); m.put(1,"India"); m.put(2,"US"); m.put(3,"Australia"); m.put(4,"Netherlands"); m.put(5,"Canada");
现在删除第一个条目-
m.pollFirstEntry()
以下是删除TreeMap的第一个条目的示例。
示例
import java.util.*;
public class Demo {
public static void main(String args[]) {
TreeMap<Integer,String> m = new TreeMap<Integer,String>();
m.put(1,"India");
m.put(2,"US");
m.put(3,"Australia");
m.put(4,"Netherlands");
m.put(5,"Canada");
System.out.println("TreeMap Elements = "+m);
System.out.println("Removing First Entry : "+m.pollFirstEntry());
System.out.println("Updated TreeMap Elements = "+m);
}
}输出结果
TreeMap Elements = {1=India, 2=US, 3=Australia, 4=Netherlands, 5=Canada}
Removing First Entry = 1=India
Updated TreeMap Elements = {2=US, 3=Australia, 4=Netherlands, 5=Canada}