Question

我有一个Python文件，其中包含以下行：

import sys

global AdminConfig
global AdminApp

此脚本在Jython上运行。我理解在函数内部使用全局关键字，但在模块级别使用“global”关键字意味着什么呢？

Answer 1

global x将当前范围中x 的范围规则更改为模块级别，因此当x已经处于模块级别时，它没有用处

澄清：

>>> def f(): # uses global xyz
...  global xyz
...  xyz = 23
... 
>>> 'xyz' in globals()
False
>>> f()
>>> 'xyz' in globals()
True

，而

>>> def f2():
...  baz = 1337 # not global
... 
>>> 'baz' in globals()
False
>>> f2() # baz will still be not in globals()
>>> 'baz' in globals()
False

但是

>>> 'foobar' in globals()
False
>>> foobar = 42 # no need for global keyword here, we're on module level
>>> 'foobar' in globals()
True

和

>>> global x # makes no sense, because x is already global IN CURRENT SCOPE
>>> x=1
>>> def f3():
...  x = 5 # this is local x, global property is not inherited or something
... 
>>> f3() # won't change global x
>>> x # this is global x again
1

模块范围的全局关键字

1 个答案: