Java TreeSet subSet()用法及代码示例

java.util.TreeSet.subSet()用于返回参数中提到的范围内的现有TreeSet的子集。该方法接受一个上限和一个下限，并返回范围内提到的所有元素。如果元素存在于集合中，则包括下限，而排除上限。本质上，它使子集大于等于下限，并且严格小于上元素。

用法:

TreeSet tree_set.subSet(Object low_element, Object up_element)

参数：

low_element：这是TreeSet的类型，它定义了评估子集的下限或起始元素。该元素包含在子集中。
up_element：这是TreeSet的类型，它定义子集要评估的上限或最后一个元素。该元素从子集中排除。

返回值：该方法返回在给定参数范围内提到的TreeSet类型的子集。

以下程序说明了java.util.TreeSet.subSet()方法：

程序1：

// Java code to illustrate subSet() 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(5); 
        tree_set.add(1); 
        tree_set.add(50); 
        tree_set.add(10); 
        tree_set.add(20); 
        tree_set.add(6); 
        tree_set.add(20); 
        tree_set.add(18); 
        tree_set.add(9); 
        tree_set.add(30); 
  
        // Creating the subset tree 
        TreeSet<Integer> sub_set = new TreeSet<Integer>(); 
  
        // Limiting the values till 5 
        sub_set = (TreeSet<Integer>)tree_set.subSet(6, 30); 
  
        // Creating an Iterator 
        Iterator iterate; 
        iterate = sub_set.iterator(); 
  
        // Displaying the tree set data 
        System.out.println("The resultant values within the sub set: "); 
  
        // Iterating through the subset 
        while (iterate.hasNext()) { 
            System.out.println(iterate.next() + " "); 
        } 
    } 
}

输出：

The resultant values within the sub set: 
6 
9 
10 
18 
20

程序2：

// Java code to illustrate subSet() method when TreeSet 
// contains elements of String type 
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 subset tree 
        TreeSet<String> sub_set = new TreeSet<String>(); 
  
        // Limiting the values till 5 
        sub_set = (TreeSet<String>)tree_set.subSet("4", "TreeSet"); 
  
        // Creating an Iterator 
        Iterator iterate; 
        iterate = sub_set.iterator(); 
  
        // Displaying the tree set data 
        System.out.println("The resultant values within the sub set: "); 
  
        // Iterating through the subset 
        while (iterate.hasNext()) { 
            System.out.println(iterate.next() + " "); 
        } 
    } 
}

输出：

The resultant values within the sub set: 
4 
Geek 
Geeks 
To

相关用法

注：本文由纯净天空筛选整理自Chinmoy Lenka大神的英文原创作品 TreeSet subSet() Method in Java。非经特殊声明，原始代码版权归原作者所有，本译文未经允许或授权，请勿转载或复制。