Java中的 EnumMap clear() 方法及示例

Java中的Java .util.EnumMap.clear() 方法用于从地图中删除所有映射。该方法不会删除映射，而只是清除映射的映射。

句法：

enum_map.clear()

参数：此方法不接受任何参数。

返回值：此方法不返回任何值。

以下程序说明了Java.util.EnumMap.clear() 方法的工作原理：
方案一：

// Java program to demonstrate clear() method
import java.util.*;
  
// An enum of geeksforgeeks ranking across
// Worldwide & in India is created
public enum gfg {
    Global,
    India
}
;
  
class Enum_map {
    public static void main(String[] args)
    {
  
        EnumMap mp = new EnumMap(gfg.class);
  
        // Values are associated in mp
        mp.put(gfg.Global, 800);
        mp.put(gfg.India, 72);
  
        // Values in mp before removing
        System.out.println("Values in map before removing " + mp);
  
        // Removing the values from mp
        mp.clear();
  
        // Values in mp after removing
        System.out.println("Values in map after removing " + mp);
    }
}

输出：

Values in map before removing {Global=800, India=72}
Values in map after removing {}

方案二：

// Java program to demonstrate clear() method
import java.util.*;
  
// An enum of fruits price is created
public enum Price_of_Fruits {
    Orange,
    Apple,
    Banana,
    Pomegranate,
    Guava
  
}
;
  
class Enum_map {
    public static void main(String[] args)
    {
  
        EnumMap mp = new EnumMap(Price_of_Fruits.class);
  
        // Values are associated in mp
        mp.put(Price_of_Fruits.Orange, 30);
        mp.put(Price_of_Fruits.Apple, 50);
        mp.put(Price_of_Fruits.Banana, 40);
        mp.put(Price_of_Fruits.Pomegranate, 120);
        mp.put(Price_of_Fruits.Guava, 20);
  
        // Values in mp before removing
        System.out.println("Values in map before removing " + mp);
  
        // Removing the values from mp
        mp.clear();
  
        // Values in mp after removing
        System.out.println("Values in map after removing " + mp);
    }
}

输出：

Values in map before removing {Orange=30, Apple=50, Banana=40, 
                                    Pomegranate=120, Guava=20}
Values in map after removing {}