Java EnumMap size()用法及代碼示例

java中的Java.util.EnumMap.size()方法用於了解Map的大小或Map中存在的元素數。

用法:

Enum_Map.size()

參數：該方法不帶任何參數。

返回值：該方法返回Map的大小。

以下示例程序旨在說明size()函數的工作方式：
示例1:

// Java program to demonstrate size() 
import java.util.*; 
  
// An enum of geeksforgeeks 
public enum gfg { 
    India_today, 
    United_States_today 
} 
; 
  
class Enum_demo { 
    public static void main(String[] args) 
    { 
  
        EnumMap<gfg, Integer> mp = new 
                    EnumMap<gfg, Integer>(gfg.class); 
  
        // Values are associated 
        mp.put(gfg.India_today, 69); 
        mp.put(gfg.United_States_today, 1073); 
  
        // Prints the map 
        System.out.println("The EnumMap: " + mp); 
  
        // Store the size of the map 
        int numberOf_kv = mp.size(); 
  
        // Prints the map_size 
        System.out.println("Size of map: " + numberOf_kv); 
    } 
}

輸出：

The EnumMap: {India_today=69, United_States_today=1073}
Size of map: 2

示例2:

// Java program to demonstrate size() 
import java.util.*; 
  
// An enum of geeksforgeeks 
public enum gfg { 
  
    India_today, 
    United_States_today 
} 
; 
  
class Enum_demo { 
    public static void main(String[] args) 
    { 
  
        EnumMap<gfg, Integer> mp = new 
                  EnumMap<gfg, Integer>(gfg.class); 
  
        // Values are associated 
        mp.put(gfg.India_today, 69); 
        mp.put(gfg.United_States_today, 1073); 
  
        // Prints the map 
        System.out.println("The EnumMap: " + mp); 
  
        // Remove mapping of this key 
        mp.remove(gfg.United_States_today); 
  
        // Prints the final map 
        System.out.println("The EnumMap: " + mp); 
  
        // Store the size pf map after removal of 
        // The key 
        int numberOf_kv = mp.size(); 
  
        // Prints the map_size 
        System.out.println("Size of map: " + numberOf_kv); 
    } 
}

輸出：

The EnumMap: {India_today=69, United_States_today=1073}
The EnumMap: {India_today=69}
Size of map: 1

相關用法

注：本文由純淨天空篩選整理自akash1295大神的英文原創作品 EnumMap size() Method in Java。非經特殊聲明，原始代碼版權歸原作者所有，本譯文未經允許或授權，請勿轉載或複製。