Python 中的枚舉類

枚舉是 Python 中用於開發枚舉的類。枚舉是綁定到常量和唯一值的一組符號成員或名稱。枚舉的成員可以通過使用這些符號名來等同。枚舉可以自己在它們上面重複。

枚舉類的特徵是:

• 用戶可以使用 type()方法檢查枚舉的類型。
• 通過使用「名稱」關鍵字，用戶可以顯示枚舉的名稱。
• 枚舉是稱為 repr()的對象的可計算字符串表示形式。

示例:

import enum
# we will use enum class for creating enumerations
class Weekdays(enum.Enum):
   Sunday = 1
   Monday = 2
   Tuesday = 3
   Wednesday = 4
   Thursday = 5
   Friday = 6
   Saturday = 7
# we will print the enum member as the string
print (" The member of Enum class as the string is : ",end = " ")
print (Weekdays.Monday)

# we will print the enum member as a repr object
print (" The member of Enum class as a repr is : ",end = " ")
print (repr(Weekdays.Sunday))

# now we will check the type of enum member
print (" The type of the member of Enum class is : ",end = " ")
print (type(Weekdays.Saturday))

# we will print name of enum member
print (" The name of the member of Enum class is : ",end = " ")
print (Weekdays.Friday.name)

輸出:

The member of Enum class as the string is :  Weekdays.Monday
The member of Enum class as a repr is :  The type of the member of Enum class is :  <enum>The name of the member of Enum class is :  Friday</enum> 

如何將枚舉打印為可列表

用戶可以將枚舉類打印為可列表。

在下面的示例中，我們將使用 for循環來打印枚舉類的所有成員。

示例:

import enum
# we will user enum class for creating enumerations
class Weekdays(enum.Enum):
   Sunday = 1
   Monday = 2
   Tuesday = 3
   Wednesday = 4
   Thursday = 5
   Friday = 6
   Saturday = 7
# now we will print all enum members by using for loop
print (" The member of Enum class are : ")
for weekday in (Weekdays):
   print(weekday)

輸出:

The member of Enum class are : 
Weekdays.Sunday
Weekdays.Monday
Weekdays.Tuesday
Weekdays.Wednesday
Weekdays.Thursday
Weekdays.Friday
Weekdays.Saturday

如何哈希枚舉類

枚舉類的成員稱為枚舉，並且也是可枚舉的。因此，這些成員可以用於集合和字典。

在下面的例子中，我們將展示用戶如何哈希枚舉類。

示例:

import enum
# we will use enum class for creating enumerations
class Days(enum.Enum):
   Sunday = 1
   Monday = 2
# we will Hash for creating a dictionary
Daytype = {}
Daytype[Days.Sunday] = 'Sun God'
Daytype[Days.Monday] = 'Mon God'
# now we will Check if the hashing is successful
if Daytype =={Days.Sunday:'Sun God',Days.Monday:'Mon God'}:
 print (" Enum class is hashed ")
else: print (" Enum class is not hashed ")

輸出:

Enum class is hashed

如何訪問枚舉成員

用戶可以通過使用成員項的值或名稱來訪問枚舉類的成員。

在下面的示例中，我們將展示用戶如何通過名稱訪問值，其中我們使用了枚舉的名稱作為索引。

示例:

import enum
# we will use enum class for creating enumerations
class Days(enum.Enum):
  Sunday = 1
  Monday = 2
  Tuesday = 3
  Wednesday = 4
  Thursday = 5 
  Friday = 6
  Saturday = 7
print('The member of Enum class accessed by name: ')
print (Days['Monday'])
print('The member of Enum class accessed by name: ')
print (Days['Friday'])
print('The member of Enum class accessed by Value: ')
print (Days(1))
print('The member of Enum class accessed by Value: ')
print (Days(5)) 

輸出:

The member of Enum class accessed by name: 
Days.Monday
The member of Enum class accessed by name: 
Days.Friday
The member of Enum class accessed by Value: 
Days.Sunday
The member of Enum class accessed by Value: 
Days.Thursday

如何比較枚舉

用戶可以簡單地通過使用比較運算符來比較枚舉。

例如:

import enum
# we will use enum class for creating enumerations
class Days(enum.Enum):
  Sunday = 1
  Monday = 2
  Tuesday = 1
  Wednesday = 4
  Thursday = 5 
  Friday = 4
  Saturday = 7
if Days.Sunday == Days.Tuesday:
   print('Match')
else: print ('Do not Match')
if Days.Monday != Days.Tuesday:
    print('Do not Match')
else: print ('Match')
if Days.Wednesday == Days.Friday:
   print('Match')
else: 
print ('Do not Match')
if Days.Thursday != Days.Friday:
    print('Do not Match')
else: 
print ('Match')

輸出:

Match
Do not Match
Match
Do not Match

結論

在本文中，我們討論了 Python 的枚舉類及其特性。我們還展示了用戶如何將枚舉類打印為可迭代列表。用戶如何哈希和訪問枚舉類的成員。