Java中的字典 size() 方法及示例

Java中 Dictionary 类的 size() 方法用于了解字典的大小或字典中存在的不同键的数量。

句法：

DICTIONARY.size()

参数：
该方法不接受任何参数。

返回值：
该方法返回字典中存在的键数。

下面的程序说明了字典的 size() 方法：
方案一：

// Java Code to illustrate size()
import java.util.*;
  
public class Dictionary_Demo {
    public static void main(String args[])
    {
  
        // Creating a dictionary of Hashtable
        Dictionary dict
            = new Hashtable();
  
        // Inserting elements into the Dictionary
        dict.put(10, "Geeks");
        dict.put(15, "4");
        dict.put(10, "Geeks");
        dict.put(25, "Welcomes");
        dict.put(30, "You");
  
        // Displaying the Dictionary
        System.out.println("Dictionary: " + dict);
  
        // Displaying the size of the dictionary
        System.out.println("The size of the dictionary is "
                           + dict.size());
    }
}

输出：

Dictionary: {10=Geeks, 30=You, 15=4, 25=Welcomes}
The size of the dictionary is 4

方案二：

// Java Code to illustrate size()
import java.util.*;
  
public class Dictionary_Demo {
    public static void main(String args[])
    {
  
        // Creating a dictionary of Hashtable
        Dictionary dict
            = new Hashtable();
  
        // Inserting elements into the table
        dict.put("Geek", 10);
        dict.put("4", 15);
        dict.put("Geeks", 20);
        dict.put("Welcomes", 25);
        dict.put("You", 30);
  
        // Displaying the Dictionary
        System.out.println("Dictionary: " + dict);
  
        // Displaying the size of the dictionary
        System.out.println("The size of the dictionary is "
                           + dict.size());
    }
}

输出：

Dictionary: {You=30, Welcomes=25, 4=15, Geeks=20, Geek=10}
The size of the dictionary is 5