Java中的向量isEmpty()方法

Java中的Java () 方法用于检查和验证 Vector 是否为空。如果 Vector 为空，则返回 True，否则返回 False。

句法：

Vector.isEmpty()

参数：此方法不带任何参数。

返回值：如果 Vector 为空，则此函数返回True ，否则返回False 。

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

方案一：

// Java code to illustrate isEmpty()
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);
  
        // Verifying if the Vector is empty or not
        System.out.println("Is the Vector empty? "
                           + vec_tor.isEmpty());
  
        // Clearing the Vector
        vec_tor.clear();
  
        // Displaying the Vector
        System.out.println("Vector after clear(): "
                           + vec_tor);
  
        // Verifying if the Vector is empty or not
        System.out.println("Is the Vector empty? "
                           + vec_tor.isEmpty());
    }
}

输出：

Vector:  [Welcome, To, Geeks, 4, Geeks]
Is the Vector empty? false
Vector after clear(): []
Is the Vector empty? true

方案二：

// Java code to illustrate isEmpty()
import java.util.*;
  
public class VectorDemo {
    public static void main(String args[])
    {
        // Creating an empty Vector
        Vector vec_tor = new Vector();
  
        // Displaying the Vector
        System.out.println("Vector:  " + vec_tor);
  
        // Verifying if the Vector is empty or not
        System.out.println("Is the Vector empty? "
                           + vec_tor.isEmpty());
    }
}

输出：

Vector:  []
Is the Vector empty? true