问题描述

在 Python 中，是否有类似的 C 预处理器语句，例如?:

In Python, is there an analogue of the C preprocessor statement such as?:

#define MY_CONSTANT 50

另外，我有一大串常量我想导入到几个类中.有没有类似的方法在 .py 文件中将常量声明为像上面这样的一长串语句并将其导入另一个 .py 文件?

Also, I have a large list of constants I'd like to import to several classes. Is there an analogue of declaring the constants as a long sequence of statements like the above in a .py file and importing it to another .py file?

编辑.

文件 Constants.py 内容如下:

#!/usr/bin/env python
# encoding: utf-8
"""
Constants.py
"""

MY_CONSTANT_ONE = 50
MY_CONSTANT_TWO = 51

而 myExample.py 内容为:

#!/usr/bin/env python
# encoding: utf-8
"""
myExample.py
"""

import sys
import os

import Constants

class myExample:
    def __init__(self):
        self.someValueOne = Constants.MY_CONSTANT_ONE + 1
        self.someValueTwo = Constants.MY_CONSTANT_TWO + 1

if __name__ == '__main__':
    x = MyClass()

编辑.

来自编译器，

NameError: "全局名称'MY_CONSTANT_ONE' 未定义"

NameError: "global name 'MY_CONSTANT_ONE' is not defined"

function init in myExample at line13 self.someValueOne =常量.MY_CONSTANT_ONE + 1 份输出程序以代码 #1 退出0.06 秒后.

function init in myExample at line 13 self.someValueOne = Constants.MY_CONSTANT_ONE + 1 copy output Program exited with code #1 after 0.06 seconds.

推荐答案

Python 没有经过预处理.你可以只创建一个文件 myconstants.py:

Python isn't preprocessed. You can just create a file myconstants.py:

MY_CONSTANT = 50

导入它们就可以了:

import myconstants
print myconstants.MY_CONSTANT * 2

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