How to fix magic number errors in Python code?

In the process of writing Python code, so-called Magic Number errors sometimes occur. This error refers to the use of undefined or unclear numbers in the code, which makes the code difficult to understand and maintain. In addition, magic numbers can also lead to some potential problems, such as when the code needs to be modified, and a magic number is inadvertently modified, causing the code to behave unexpectedly.

So, how to solve magic number errors in Python code? Here are some suggestions:

1. Define constants

Using constants instead of magic numbers is one of the best ways to fix magic number errors. Define constants as global variables at the top of your code or in a separate module and reference them when needed. In this way, if you need to modify the value of a constant in the code, you only need to modify one definition, instead of having to find all the places in the code where the number is used and modify it.

Example:

MAX_VALUE = 100  # 定义一个常量
for i in range(MAX_VALUE):  # 使用常量
    print(i)

2. Enumeration type

The enumeration type is a way of binding a constant to a name, which can better Describes a set of possible values. Using enumeration types can make your code more readable and easier to maintain.

Example:

from enum import Enum

class Size(Enum):
    SMALL = 1
    MEDIUM = 2
    LARGE = 3

size = Size.MEDIUM  # 使用枚举类型
if size == Size.SMALL:
    print("Small size selected")
elif size == Size.MEDIUM:
    print("Medium size selected")
else:
    print("Large size selected")

3. Use named parameters

Using named parameters when calling functions can make the code clearer and easier to understand, and also Magic numbers can be avoided.

Example:

def draw_rectangle(x, y, width=10, height=10):  # 定义一个函数，使用命名参数
    pass

draw_rectangle(2, 4, width=100, height=50)  # 使用函数，避免使用魔术数字

4. Abstraction

Abstracting complex calculation processes into functions or classes can make the code more modular and easier to maintain . At the same time, constants or enumeration types can also be defined during the abstraction process to avoid using magic numbers.

Example:

def calculate_area(width, height):
    return width * height

area = calculate_area(10, 20)  # 使用函数，避免使用魔术数字

In short, using the above method, we can avoid using magic numbers, making the code clearer, easier to understand and maintain. Although these methods may add some extra code and work, the improvement in code readability and maintainability is worth it.

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