Java中的EnumMap put（）方法-yiteyi-C++库

爪哇。util。地图。放( 关键，价值 )方法用于关联指定的键值对。在这种情况下，如果重复这些值，则会替换旧值。

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语法：

Enum_Map.put(key, value)

使用的参数： 该方法采用两个参数。

钥匙 –它是与值关联的指定键。
价值 –它是与指定键关联的值。

返回值： 函数返回与指定键关联的旧值。

下面的程序说明了put的工作原理( 关键，价值 )方法： 项目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);                   
                                         }                   
                     }                   

输出：

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

项目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);                   
                                         }                   
                     }                   

输出：

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

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