Java中的 Vector contains() 方法

Java.util.vector.contains()方法用于检查向量中是否存在特定元素。所以基本上它用于检查向量是否包含任何特定元素。

句法：

Vector.contains(Object element)

参数：此方法采用向量类型的强制参数元素。这是需要测试的元素是否存在于向量中。

返回值：如果元素存在于向量中，则此方法返回True ，否则返回False 。

下面的程序说明了Java.util.Vector.contains() 方法：

方案一：

// Java code to illustrate contains()
import java.util.*;
  
public class VectorDemo {
    public static void main(String args[])
    {
        // Creating an empty Vector
        Vector vec_tor = new Vector();
  
        // Use add() method to add elements into the Vector
        vec_tor.add("Welcome");
        vec_tor.add("To");
        vec_tor.add("Geeks");
        vec_tor.add("4");
        vec_tor.add("Geeks");
  
        // Displaying the Vector
        System.out.println("Vector: " + vec_tor);
  
        // Check for "Geeks" in the Vector
        System.out.println("Does the vector contains 'Geeks'? "
                           + vec_tor.contains("Geeks"));
  
        // Check for "4" in the Vector
        System.out.println("Does the Vector contains '4'? "
                           + vec_tor.contains("4"));
  
        // Check if the Queue contains "No"
        System.out.println("Does the Queue contains 'No'? "
                           + vec_tor.contains("No"));
    }
}

输出：

Vector: [Welcome, To, Geeks, 4, Geeks]
Does the vector contains 'Geeks'? true
Does the Vector contains '4'? true
Does the Queue contains 'No'? false

方案二：

// Java code to illustrate contains()
import java.util.*;
  
public class VectorDemo {
    public static void main(String args[])
    {
        // Creating an empty Vector
        Vector vec_tor = new Vector();
  
        // Use add() method to add elements into the Vector
        vec_tor.add(10);
        vec_tor.add(15);
        vec_tor.add(30);
        vec_tor.add(20);
        vec_tor.add(5);
  
        // Displaying the Vector
        System.out.println("Vector: " + vec_tor);
  
        // Check for "Geeks" in the Vector
        System.out.println("Does the vector contains 'Geeks'? "
                           + vec_tor.contains("Geeks"));
  
        // Check for "4" in the Vector
        System.out.println("Does the Vector contains '4'? "
                           + vec_tor.contains("4"));
  
        // Check if the vector contains "No"
        System.out.println("Does the Vector contains 'No'? "
                           + vec_tor.contains("No"));
    }
}

输出：

Vector: [10, 15, 30, 20, 5]
Does the vector contains 'Geeks'? false
Does the Vector contains '4'? false
Does the Vector contains 'No'? false