📜  使用示例在Java中设置 contains() 方法

📅  最后修改于: 2022-05-13 01:55:26.321000             🧑  作者: Mango

使用示例在Java中设置 contains() 方法

Java.util.Set.contains() 方法用于检查特定元素是否存在于 Set 中。所以基本上它用于检查 Set 是否包含任何特定元素。

句法:

boolean contains(Object element)

参数:参数元素是Set类型。这是需要测试的元素是否存在于集合中。

返回值:如果元素存在于集合中,则该方法返回 true,否则返回 False。

下面的程序说明了Java.util.Set.contains() 方法:

// Java code to illustrate Set.contains() method
import java.io.*;
import java.util.*;
  
public class HashSetDemo {
    public static void main(String args[])
    {
        // Creating an empty Set
        Set set = new HashSet();
  
        // Using add() method to add elements into the Set
        set.add("Welcome");
        set.add("To");
        set.add("Geeks");
        set.add("4");
        set.add("Geeks");
  
        // Displaying the Set
        System.out.println("Set: " + set);
  
        // Check for "Geeks" in the set
        System.out.println("Does the Set contains 'Geeks'? "
                           + set.contains("Geeks"));
  
        // Check for "4" in the set
        System.out.println("Does the Set contains '4'? "
                           + set.contains("4"));
  
        // Check if the Set contains "No"
        System.out.println("Does the Set contains 'No'? "
                           + set.contains("No"));
    }
}
输出:
Set: [4, Geeks, Welcome, To]
Does the Set contains 'Geeks'? true
Does the Set contains '4'? true
Does the Set contains 'No'? false

参考:https: Java Java.lang.Object)