Question

我的问题似乎相当基本,但我似乎无法在任何地方找到任何帮助。

file_a.py >>

from xyz import XYZ
class A:
    .
    .
    .

file_b.py >>

import file_a
from file_a import A
class B(A):
    def __init__(self):
        A.__init__(self)

    def someMethod(self):
        XYZ.doSomething()

XYZ.doSomething() fails saying NameError: name XYZ is not defined Even standard imports like import sys done from file_a does not seem to render it usable in file_b. I assumed that should work. Is my understanding wrong? If yes, then is there a way to have common imports and global variables across files? (If it is of nay help, I ve been a C++ and java programmer and am now starting to use python. )

Answer 1

我的理解是否是错误的?

是的,因为从文件_a import A到进口的“A,进入.file_b 。 <代码>file_a <>/code>的名称仅剩下。如果不是这样的话,那么两个辛迪加就没有什么意义:

import modulename
from modulename import something

如果你的想法是正确的,那么,在第二种形式之后,你总是能够使用<条码>。

如果是,那么是否有办法在档案中实现共同进口和全球变量?

是的,有星号<代码>*的操作者:

from modulename import *

但这带来了名称空间污染问题,例如,从文件_a import * 进口到file_b。并且,在<代码>上所做的所有进口产品——a。页: 1 我相信我会这样做!

When for some reason from module import * is needed, a workaround to namespace pollution is to define in module the variable __all__, which whitelists what should be imported with the star operator.

HTH!

Answer 2

当你进口一个模块时,该模块中确定的所有变量都可以在其名称空间上获得。因此,如果<代码>XYZ,可在file_a上查阅。页: 1 页: 1

The general idea here is that your namespace shouldn t be cluttered with the contents of other namespaces.

Answer 3

是的,你们的理解是错误的。每个单元都有自己的名称空间,只有你在该档案中明确进口的物品可以在这个名称空间获得。

Contrary to other answers, it is not particularly Pythonic to refer to file_a.XYZ, although this will work. Instead, you should import XYZ and sys at the top of file_b.

Answer 4

import file_a
from file_a import A

I think the problem is: you do not import XYZ really!

from fila_a import *

它可以解决你的问题,但这不是一种好的办法。

页: 1

from file_a import XYZ

是做的?

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