• Tags
  •         
  • www.breakyizhan.com
  •    

    IdentityHashMap类的java.util.IdentityHashMap.size()方法用于获取IdentityHashMap的大小,该大小是指Map中键值对或映射的数量。

    句法:

    Identity_Hash_Map.size()

    参数:该方法不接受任何参数。

    返回值:该方法返回映射的大小,这也表示映射中存在的键值对的数量。

    下面的程序说明了java.util.IdentityHashMap.size()方法

    程序1

    // Java code to illustrate the size() method
    import java.util.*;
    
    public class Identity_Hash_Map_Demo {
        public static void main(String[] args)
        {
    
            // Creating an empty IdentityHashMap
            Map<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);
    
            // Displaying the size of the map
            System.out.println("The size of the map is " + 
                                        identity_hash.size());
        }
    }
    

    输出:

    Initial Mappings are: {Geeks=20, Welcomes=25, You=30, 4=15}
    The size of the map is 4

    程序2:

    // Java code to illustrate the size() method
    import java.util.*;
    
    public class Identity_Hash_Map_Demo {
        public static void main(String[] args)
        {
    
            // Creating an empty IdentityHashMap
            Map<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);
    
            // Displaying the size of the map
            System.out.println("The size of the map is " + 
                                         identity_hash.size());
        }
    }
    

    输出:

    Initial Mappings are: {Welcomes=25, 4=15, You=30, Geeks=20}
    The size of the map is 4

     
    转载请保留页面地址:https://www.breakyizhan.com/java/5345.html