如何在python中设置全局常量变量
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how to set global const variables in python
提问by gen
I am building a solution with various classes and functions all of which need access to some global consants to be able to work appropriately. As there is no constin python, what would you consider best practice to set a kind of global consants.
我正在构建一个包含各种类和函数的解决方案，所有这些类和函数都需要访问一些全局常量才能正常工作。由于constpython中没有，您认为设置一种全局常量的最佳实践是什么。
global const g = 9.8
So I am looking for a kind of the above
所以我正在寻找一种上述
edit: How about:
编辑：怎么样：
class Const():
@staticmethod
def gravity():
return 9.8
print 'gravity: ', Const.gravity()
?
?
采纳答案by John La Rooy
You cannot define constants in Python. If you find some sort of hack to do it, you would just confuse everyone.
您不能在 Python 中定义常量。如果你找到某种黑客来做到这一点，你只会让每个人都感到困惑。
To do that sort of thing, usually you should just have a module - globals.pyfor example that you import everywhere that you need it
要做那种事情，通常你应该只有一个模块——globals.py例如，你可以在任何需要它的地方导入
回答by chhantyal
General convention is to define variables with capital and underscores and not change it. Like,
一般约定是用大写和下划线定义变量而不是改变它。喜欢，
GRAVITY = 9.8
However, it is possible to create constants in Python using namedtuple
但是，可以使用 Python 在 Python 中创建常量 namedtuple
import collections
Const = collections.namedtuple('Const', 'gravity pi')
const = Const(9.8, 3.14)
print(const.gravity) # => 9.8
# try to change, it gives error
const.gravity = 9.0 # => AttributeError: can't set attribute
For namedtuple, refer to docs here
对于namedtuple，请参阅此处的文档
