Java EnumMap put()用法及代碼示例

Java中的Java.util.EnumMap.put(key，value)方法用於關聯指定的鍵-值對。在這種情況下，如果重複這些值，則替換較舊的值。

用法:

Enum_Map.put(key, value)

使用的參數：該方法有兩個參數。

key–它是與值關聯的指定鍵。
value–它是與指定鍵關聯的值。

返回值：該函數返回與指定鍵關聯的舊值。

以下程序說明了put(key，value)方法的用法原理：
示例1:

// Java program to demonstrate keySet() 
import java.util.*; 
  
// An enum of geeksforgeeks 
public enum gfg { 
    Global_today, 
    India_today, 
    China 
} 
; 
  
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.Global_today, 799); 
        mp.put(gfg.India_today, 69); 
  
       // Display the initial map 
       System.out.println("The map is: " + mp); 
  
        // Stores the old value associated with the key 
        int prev_value = mp.put(gfg.India_today, 72); 
  
        // Prints the old value 
        System.out.println("Previous value: " + prev_value); 
  
       // Display the final map 
       System.out.println("The final map is: " + mp); 
    } 
}

輸出：

The map is: {Global_today=799, India_today=69}
Previous value: 69
The final map is: {Global_today=799, India_today=72}

示例2:

// Java program to demonstrate the working of keySet() 
import java.util.*; 
  
// an enum of geeksforgeeks 
// ranking globally and in india 
public enum gfg { 
    Global_today, 
    India_today, 
    China_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.Global_today, 799); 
        mp.put(gfg.India_today, 69); 
  
       // Display the initial map 
       System.out.println("The map is: " + mp); 
  
        // Stores the old value associated with the key 
        int prev_value = mp.put(gfg.Global_today, 800); 
  
        // Prints the old value 
        System.out.println("Previous value: " + prev_value); 
  
       // Display the final map 
       System.out.println("The final map is: " + mp); 
    } 
}

輸出：

The map is: {Global_today=799, India_today=69}
Previous value: 799
The final map is: {Global_today=800, India_today=69}

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 put() 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。