Java 中的 EnumMap entrySet()方法
原文:https://www . geesforgeks . org/enummap-entryset-method-in-Java/
Java 中的 Java.util.EnumMap.entrySet()方法用于创建一组包含在 EnumMap 中的元素。它基本上返回枚举映射的集合视图。
语法:
enum_map.entrySet()
参数:该方法不取任何参数。
返回值:该方法返回此 enum_map 中包含的映射的集合视图。
下面的程序说明了 entrySet()方法:
程序 1:
// Java program to demonstrate entrySet() method
import java.util.*;
// An enum of gfg rank is created
public enum rank_countries {
India,
United_States,
China,
Japan,
Canada,
Russia
}
;
class Enum_map {
public static void main(String[] args)
{
EnumMap<rank_countries, Integer> mp = new
EnumMap<rank_countries, Integer>(rank_countries.class);
// Values are associated in mp
mp.put(rank_countries.India, 72);
mp.put(rank_countries.United_States, 1083);
mp.put(rank_countries.China, 4632);
mp.put(rank_countries.Japan, 6797);
// Map view
System.out.println("Map view: " + mp);
// Creating a new set of the mappings
// contained in map
Set<Map.Entry<rank_countries, Integer> > set_view =
mp.entrySet();
// Set view of the mappings
System.out.println("Set view of the map: " + set_view);
}
}
Output:
Map view: {India=72, United_States=1083, China=4632, Japan=6797}
Set view of the map: [India=72, United_States=1083, China=4632, Japan=6797]
程序 2:
// Java program to demonstrate entrySet() method
import java.util.*;
// An enum of gfg ranking worldwide and in india
public enum gfg {
Global_2018,
India_2018
};
class Enum_map {
public static void main(String[] args)
{
EnumMap<gfg, Integer> mp = new
EnumMap<gfg, Integer>(gfg.class);
// Values are associated in mp
mp.put(gfg.Global_2018, 800);
mp.put(gfg.India_2018, 72);
// Mapping view
System.out.println("Mapping view: " + mp);
// Creating a new set of the mappings
Set<Map.Entry<gfg, Integer> > set_view =
mp.entrySet();
// Set view of the mappings
System.out.println("Set view of the map: "
+ set_view);
}
}
Output:
Mapping view: {Global_2018=800, India_2018=72}
Set view of the map: [Global_2018=800, India_2018=72]
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