Java Vector isEmpty()方法

Java.util.Vector .isEmpty()方法用于检查和验证一个向量是否为空。如果Vector是空的，它返回True，否则它返回False。

语法

Vector.isEmpty()

参数： 此方法不接受任何参数。

返回值： 如果Vector是空的，该函数返回True，否则返回False。

以下程序说明了Java.util.Vector.isEmpty()方法。

程序1 :

// Java code to illustrate isEmpty()
import java.util.*;
  
public class VectorDemo {
    public static void main(String args[])
    {
        // Creating an empty Vector
        Vector<String> vec_tor = new Vector<String>();
  
        // 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

程序2

// Java code to illustrate isEmpty()
import java.util.*;
  
public class VectorDemo {
    public static void main(String args[])
    {
        // Creating an empty Vector
        Vector<Integer> vec_tor = new Vector<Integer>();
  
        // 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