Java AbstractSet contains()用法及代码示例

Java AbstractSet的contains()方法用于检查集合中是否存在元素。它使用元素作为参数，如果元素存在于集合中，则返回True。

用法:

public boolean contains(Object element)

参数：参数element 是设置的类型。此参数表示需要在集合中检查其出现的元素。

返回值：该方法返回一个布尔值。如果元素存在于集合中，则返回True；否则返回False。

以下示例程序旨在说明AbstractSet.contains()方法：

示例1:

// Java code to illustrate 
// AbstractSet.contains() 
  
import java.util.*; 
  
public class GFG { 
    public static void main(String args[]) 
    { 
  
        // Creating an empty set 
        AbstractSet<String> 
            abs = new TreeSet<String>(); 
  
        // Use add() method to add 
        // elements in the set 
        abs.add("Geeks"); 
        abs.add("for"); 
        abs.add("Geeks"); 
        abs.add("10"); 
        abs.add("20"); 
  
        // Displaying the set 
        System.out.println("AbstractSet: "
                           + abs); 
  
        // Check if the set contains "Hello" 
        System.out.println("\nDoes the set"
                           + " contains 'Hello': "
                           + abs.contains("Hello")); 
  
        // Check if the set contains "20" 
        System.out.println("Does the set"
                           + " contains '20': "
                           + abs.contains("20")); 
  
        // Check if the set contains "Geeks" 
        System.out.println("Does the set"
                           + " contains 'Geeks': "
                           + abs.contains("Geeks")); 
    } 
}

输出：

AbstractSet: [10, 20, Geeks, for]

Does the set contains 'Hello': false
Does the set contains '20': true
Does the set contains 'Geeks': true

示例2:

// Java code to illustrate 
// AbstractSet.contains() 
  
import java.util.*; 
  
public class GFG { 
    public static void main(String args[]) 
    { 
  
        // Creating an empty set 
        AbstractSet<Integer> 
            abs = new TreeSet<Integer>(); 
  
        // Use add() method to add 
        // elements in the set 
        abs.add(10); 
        abs.add(20); 
        abs.add(30); 
        abs.add(40); 
        abs.add(50); 
  
        // Displaying the set 
        System.out.println("AbstractSet:"
                           + abs); 
  
        // Check if the set contains 10 
        System.out.println("\nDoes the set "
                           + "contains '10': "
                           + abs.contains(10)); 
  
        // Check if the set contains 50 
        System.out.println("\nDoes the set"
                           + " contains '50': "
                           + abs.contains(50)); 
  
        // Check if the set contains 100 
        System.out.println("Does the set"
                           + " contains '100': "
                           + abs.contains(100)); 
    } 
}

输出：

AbstractSet:[10, 20, 30, 40, 50]

Does the set contains '10': true

Does the set contains '50': true
Does the set contains '100': false

相关用法

注：本文由纯净天空筛选整理自Code_r大神的英文原创作品 AbstractSet contains() method in Java with Example。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。