IdentityHashMap在Java中包含value（）方法-yiteyi-C++库

爪哇。util。身份地图。containsValue（）方法用于检查特定值是否由IdentityHashMap中的一个或多个键映射。它将该值作为参数，如果该值由映射中的任何键映射，则返回True。

null

语法：

Identity_HashMap.containsValue(Object Value)

参数： 该方法只需要一个参数价值对象类型，并指其映射应该由映射内的任何键检查的值。

返回值： 如果检测到值的映射为false，则该方法返回boolean true。

下面的程序演示了java。util。身份地图。containsValue（）方法：

项目1： 将字符串值映射到整数键。

                     // Java code to illustrate the containsValue() method                   
                     import                               java.util.*;                   
                             
                     public                               class                               Identity_Hash_Map_Demo {                   
                                         public                               static                               void                               main(String[] args)                   
                                         {                   
                             
                                         // Creating an empty IdentityHashMap                   
                                         IdentityHashMap<Integer, String> identity_hash =                   
                                         new                               IdentityHashMap<Integer, String>();                   
                             
                                         // Mapping string values to int keys                   
                                         identity_hash.put(                               10                               ,                               "Geeks"                               );                   
                                         identity_hash.put(                               15                               ,                               "4"                               );                   
                                         identity_hash.put(                               20                               ,                               "Geeks"                               );                   
                                         identity_hash.put(                               25                               ,                               "Welcomes"                               );                   
                                         identity_hash.put(                               30                               ,                               "You"                               );                   
                             
                                         // Displaying the IdentityHashMap                   
                                         System.out.println(                               "Initial Mappings are: "                               +                   
                                         identity_hash);                   
                             
                                         // Checking for the Value 'Geeks'                   
                                         System.out.println(                               "Is the value 'Geeks' present? "                               +                   
                                         identity_hash.containsValue(                               "Geeks"                               ));                   
                             
                                         // Checking for the Value 'World'                   
                                         System.out.println(                               "Is the value 'World' present? "                               +                   
                                         identity_hash.containsValue(                               "World"                               ));                   
                                         }                   
                     }                   

输出：

Initial Mappings are: {10=Geeks, 30=You, 20=Geeks, 25=Welcomes, 15=4}
Is the value 'Geeks' present? true
Is the value 'World' present? false

项目2： 将整数值映射到字符串键。

                     // Java code to illustrate the containsValue() method                   
                     import                               java.util.*;                   
                             
                     public                               class                               Identity_Hash_Map_Demo {                   
                                         public                               static                               void                               main(String[] args)                   
                                         {                   
                             
                                         // Creating an empty IdentityHashMap                   
                                         IdentityHashMap<String, Integer> identity_hash =                   
                                         new                               IdentityHashMap<String, Integer>();                   
                             
                                         // Mapping int values to string keys                   
                                         identity_hash.put(                               "Geeks"                               ,                               10                               );                   
                                         identity_hash.put(                               "4"                               ,                               15                               );                   
                                         identity_hash.put(                               "Geeks"                               ,                               20                               );                   
                                         identity_hash.put(                               "Welcomes"                               ,                               25                               );                   
                                         identity_hash.put(                               "You"                               ,                               30                               );                   
                             
                                         // Displaying the IdentityHashMap                   
                                         System.out.println(                               "Initial Mappings are: "                               +                   
                                         identity_hash);                   
                             
                                         // Checking for the Value '10'                   
                                         System.out.println(                               "Is the value '10' present? "                               +                   
                                         identity_hash.containsValue(                               10                               ));                   
                             
                                         // Checking for the Value '30'                   
                                         System.out.println(                               "Is the value '30' present? "                               +                   
                                         identity_hash.containsValue(                               30                               ));                   
                             
                                         // Checking for the Value '40'                   
                                         System.out.println(                               "Is the value '40' present? "                               +                   
                                         identity_hash.containsValue(                               40                               ));                   
                                         }                   
                     }                   

输出：

Initial Mappings are: {Geeks=20, Welcomes=25, You=30, 4=15}
Is the value '10' present? false
Is the value '30' present? true
Is the value '40' present? false

注：相同的操作可以在不同数据类型的变化和组合的任何类型的映射中执行。

文章版权归作者所有，未经允许请勿转载。

THE END

Java