Java TreeSet tailSet()方法

java.util.TreeSet.tailSet()方法用于为一个树形集合设置一个起始点，以排序的方式返回所有大于作为参数传递给该方法的元素，包括该元素（如果该元素在树中被提及）。

语法

TreeSet tail_set.tailSet(Object element)

参数： 参数元素是TreeSet的类型，是树的起点，允许从这个起点返回大于参数中提到的值，包括该元素。

返回值： 该方法以排序的方式返回大于参数中提到的元素的那部分值，包括参数。

下面的程序说明了java.util.TreeSet.tailSet()的使用。

程序1： 在一个排序的TreeSet中。

// Java code to illustrate TreeSet.tailSet() method
import java.io.*;
import java.util.Iterator;
import java.util.TreeSet;
  
public class Tree_Set_Demo {
    public static void main(String[] args)
    {
  
        // Creating an empty TreeSet
        TreeSet<Integer> tree_set = new TreeSet<Integer>();
  
        // Adding the elements using add()
        tree_set.add(1);
        tree_set.add(2);
        tree_set.add(3);
        tree_set.add(4);
        tree_set.add(5);
        tree_set.add(10);
        tree_set.add(20);
        tree_set.add(30);
        tree_set.add(40);
        tree_set.add(50);
  
        // Creating the tailSet tree
        TreeSet<Integer> tail_set = new TreeSet<Integer>();
  
        // Limiting the values till 5
        tail_set = (TreeSet<Integer>)tree_set.tailSet(10);
  
        // Creating an Iterator
        Iterator iterate;
        iterate = tail_set.iterator();
  
        // Displaying the tree set data
        System.out.println("The resultant values from the tail: ");
  
        // Iterating through the tailSet
        while (iterate.hasNext()) {
            System.out.println(iterate.next() + " ");
        }
    }
}

输出：

The resultant values from the tail: 
10 
20 
30 
40 
50

程序2： 在一个未排序的TreeSet中。

// Java code to illustrate tailSet()
import java.io.*;
import java.util.Iterator;
import java.util.TreeSet;
  
public class Tree_Set_Demo {
    public static void main(String[] args)
    {
  
        // Creating an empty TreeSet
        TreeSet<Integer> tree_set = new TreeSet<Integer>();
  
        // Adding the elements using add()
        tree_set.add(9);
        tree_set.add(2);
        tree_set.add(100);
        tree_set.add(40);
        tree_set.add(50);
        tree_set.add(10);
        tree_set.add(20);
        tree_set.add(30);
        tree_set.add(15);
        tree_set.add(16);
  
        // Creating the tailSet tree
        TreeSet<Integer> tail_set = new TreeSet<Integer>();
  
        // Limiting the values till 5
        tail_set = (TreeSet<Integer>)tree_set.tailSet(25);
  
        // Creating an Iterator
        Iterator iterate;
        iterate = tail_set.iterator();
  
        // Displaying the tree set data
        System.out.println("The resultant values from the tail: ");
  
        // Iterating through the tailSet
        while (iterate.hasNext()) {
            System.out.println(iterate.next() + " ");
        }
    }
}

输出：

The resultant values from the tail: 
30 
40 
50 
100

程序3： 在一个未排序的TreeSet中，但有字符串类型的元素。

// Java code to illustrate tailSet()
import java.io.*;
import java.util.Iterator;
import java.util.TreeSet;
  
public class Tree_Set_Demo {
    public static void main(String[] args)
    {
  
        // Creating an empty TreeSet
        TreeSet<String> tree_set = new TreeSet<String>();
  
        // Adding the elements using add()
        tree_set.add("Welcome");
        tree_set.add("To");
        tree_set.add("Geek");
        tree_set.add("4");
        tree_set.add("Geeks");
        tree_set.add("TreeSet");
  
        // Creating the tailSet tree
        TreeSet<String> tail_set = new TreeSet<String>();
  
        // Limiting the values till 5
        tail_set = (TreeSet<String>)tree_set.tailSet("To");
  
        // Creating an Iterator
        Iterator iterate;
        iterate = tail_set.iterator();
  
        // Displaying the tree set data
        System.out.println("The resultant values from the tail: ");
  
        // Iterating through the tailSet
        while (iterate.hasNext()) {
            System.out.println(iterate.next() + " ");
        }
    }
}

输出：

The resultant values from the tail: 
To 
TreeSet 
Welcome