Java LinkedHashSet contains()用法及代码示例

如果此集合包含指定的元素，则使用java.util.LinkedHashSet类的contains()方法返回true，否则返回false。

用法:

public boolean contains(Object o)

参数：此方法将元素o作为参数，要测试其是否存在于此集中。

返回值：如果此集合包含指定的元素，则此方法返回true。

以下示例说明了contains()方法。

示例1:

// Java program to demonstrate 
// contains() method 
// for String value 
  
import java.util.*; 
  
public class GFG1 { 
    public static void main(String[] argv) throws Exception 
    { 
        try { 
  
            // Create the object of LinkedHashSet<String> 
            LinkedHashSet<String> 
                linkset = new LinkedHashSet<String>(); 
  
            // populate hash set 
            linkset.add("A"); 
            linkset.add("B"); 
            linkset.add("C"); 
  
            // print the LinkedHashSet 
            System.out.println("LinkedHashSet: "
                               + linkset); 
  
            // check the existence of element 
            // using method contains() 
            boolean exist = linkset.contains("C"); 
  
            // print the result 
            System.out.println("Is the element"
                               + " 'C' present: "
                               + exist); 
        } 
  
        catch (NullPointerException e) { 
            System.out.println("Exception thrown : " + e); 
        } 
    } 
}

输出：

LinkedHashSet: [A, B, C]
Is the element 'C' present: true

示例2:

// Java program to demonstrate 
// contains() method 
// for Integer value 
  
import java.util.*; 
  
public class GFG1 { 
    public static void main(String[] argv) throws Exception 
    { 
        try { 
  
            // Create the object of LinkedHashSet<Integer> 
            LinkedHashSet<Integer> 
                linkset = new LinkedHashSet<Integer>(); 
  
            // populate hash set 
            linkset.add(10); 
            linkset.add(20); 
            linkset.add(30); 
  
            // print the LinkedHashSet 
            System.out.println("LinkedHashSet: "
                               + linkset); 
  
            // check the existence of element 
            // using method contains() 
            boolean exist = linkset.contains(25); 
  
            // print the result 
            System.out.println("Is the element"
                               + " '25' present: "
                               + exist); 
        } 
  
        catch (NullPointerException e) { 
            System.out.println("Exception thrown : " + e); 
        } 
    } 
}

输出：

LinkedHashSet: [10, 20, 30]
Is the element '25' present: false

相关用法

注：本文由纯净天空筛选整理自RohitPrasad3大神的英文原创作品 LinkedHashSet contains() method in Java with Examples。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。