Java中的EnumMap putAll（map）方法-yiteyi-C++库

爪哇。util。地图。普塔尔( 地图 )方法用于将所有映射从一个映射复制到新映射。旧的映射将替换为新的映射。

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语法：

void putAll(map)

参数： 该方法采用一个参数地图 .这是要复制到新地图上的地图。

返回值 该方法不返回任何值。

下面的程序演示了putAll（）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_today                   
                     };                   
                             
                     class                               Enum_demo {                   
                                         public                               static                               void                               main(String[] args)                   
                                         {                   
                             
                                         EnumMap<gfg, Integer> mp1 =                   
                                         new                               EnumMap<gfg, Integer>(gfg.                               class                               );                   
                             
                                         EnumMap<gfg, Integer> mp2 =                   
                                         new                               EnumMap<gfg, Integer>(gfg.                               class                               );                   
                             
                                         // Values are associated                   
                                         mp1.put(gfg.Global_today,                               799                               );                   
                                         mp1.put(gfg.India_today,                               69                               );                   
                             
                                         // Copies all the mappings of mp1 to mp2                   
                                         mp2.putAll(mp1);                   
                             
                                         // Prints the first map                   
                                         System.out.println(                               "Mappings in Map1: "                               + mp1);                   
                             
                                         // Prints the second map                   
                                         System.out.println(                               "Mappings in Map2: "                               + mp2);                   
                                         }                   
                     }                   

输出：

Mappings in Map1: {Global_today=799, India_today=69}
Mappings in Map2: {Global_today=799, India_today=69}

项目2：

                     // Java program to demonstrate the working of keySet()                   
                     import                               java.util.*;                   
                             
                     // an enum of geeksforgeeks                   
                     // visitors in India and United States                   
                     public                               enum                               gfg {                   
                             
                                         India_today,                   
                                         United_States_today                   
                     }                   
                     ;                   
                             
                     class                               Enum_demo {                   
                                         public                               static                               void                               main(String[] args)                   
                                         {                   
                             
                                         EnumMap<gfg, String> mp1 =                   
                                         new                               EnumMap<gfg, String>(gfg.                               class                               );                   
                             
                                         EnumMap<gfg, String> mp2 =                   
                                         new                               EnumMap<gfg, String>(gfg.                               class                               );                   
                             
                                         // Values are associated                   
                                         mp1.put(gfg.India_today,                               "61.8%"                               );                   
                                         mp1.put(gfg.United_States_today,                               "18.2%"                               );                   
                             
                                         // Copies all the mappings of mp1 to mp2                   
                                         mp2.putAll(mp1);                   
                             
                                         // Prints the first map                   
                                         System.out.println(                               "Mappings in Map1: "                               + mp1);                   
                             
                                         // Prints the second map                   
                                         System.out.println(                               "Mappings in Map2: "                               + mp2);                   
                                         }                   
                     }                   

输出：

Mappings in Map1: {India_today=61.8%, United_States_today=18.2%}
Mappings in Map2: {India_today=61.8%, United_States_today=18.2%}

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