How to use the enum module to define enumeration types in Python 2.x

How to use the enum module to define enumeration types in Python 2.x

Introduction:
An enumeration is a data type that limits the value of a variable to a limited range. Use Enumeration types can make code clearer and more readable. In Python 2.x, we can use the enum module to define enumeration types. This article will introduce how to use the enum module to define and use enumeration types, and give corresponding code examples.

1. Import enum module
   Before using the enum module, you first need to import the module. In Python 2.x, you can use the following statement to import the enum module:

from enum import Enum

2. Define enumeration types
   It is very simple to use the enum module to define enumeration types. In Python 2.x , just create a class that inherits from Enum. In this class, you can use the equal sign assignment when defining enumeration values.

The following is a sample code that demonstrates how to define a Weekday enumeration type and give each enumeration value a corresponding name:

from enum import Enum

class Weekday(Enum):
    MONDAY = 1
    TUESDAY = 2
    WEDNESDAY = 3
    THURSDAY = 4
    FRIDAY = 5
    SATURDAY = 6
    SUNDAY = 7

In this sample code, we A Weekday enumeration type is defined, which contains seven enumeration values, corresponding to Monday to Sunday.

3. Using enumeration types
   After defining the enumeration type, we can use the enumeration value directly. In Python 2.x, the syntax for using enumeration values ​​is: enumeration type name.enumeration value name.

The following is a sample code that shows how to use the Weekday enumeration type:

print(Weekday.MONDAY)  # 输出：Weekday.MONDAY
print(Weekday.SUNDAY)  # 输出：Weekday.SUNDAY

In this sample code, we print the two enumeration values ​​​​in the Weekday enumeration type .

4. Comparing enumeration values
   In Python 2.x, we can use the "==" operator to compare whether enumeration values ​​are equal.

The following is a sample code that shows how to compare two enumeration values ​​in the Weekday enumeration type:

if Weekday.MONDAY == Weekday.MONDAY:
    print("Monday is equal to Monday")  # 输出：Monday is equal to Monday

In this sample code, we compare two Weekday The enumeration value in the enumeration type is subject to conditional judgment based on the comparison result.

Summary:
This article introduces how to use the enum module to define enumeration types in Python 2.x, and gives corresponding code examples. By using enumeration types we can make the code clearer and readable. In actual development, when you need to limit the value range of a variable, using enumeration types will be very helpful.

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