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Python命名空间
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命名空間namespace 定義
內建命名空間(Builtins)：在啟動python解釋器時創建，我覺得是特殊的全局命名空間，因為它相當于導入了builtins 模塊 全局命名空間(Global)：在導入模塊時創建 局部命名空間(Local)：在調用函數時創建 內嵌函數命名空間(Enclosing)：函數內嵌函數時的特殊局部命名空間 創建
Python 3.7.0 (default, Jun 28 2018, 07:39:16)
[Clang 4.0.1 (tags/RELEASE_401/final)] :: Anaconda, Inc. on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> def func1():
... name = 1
... print('localspace:',locals())
... print('globalspace:',globals())
... def func2():
... print('before func1 local:',locals())
... print('before func1 global:',globals())
... ayu = name
... print('after func1 local:',locals()) #1
... print('after func1 global:',globals())
... func2() #2
... print('after func2 local:',locals())
... print('after func2 global:',globals())
...
>>> func1()
localspace: {'name': 1}
globalspace: {'__name__': '__main__', '__doc__': None, '__package__': None, '__loader__': <class '_frozen_importlib.BuiltinImporter'>, '__spec__': None, '__annotations__': {}, '__builtins__': <module 'builtins' (built-in)>, 'func1': <function func1 at 0x10384c598>}
before func1 local: {'name': 1}
before func1 global: {'__name__': '__main__', '__doc__': None, '__package__': None, '__loader__': <class '_frozen_importlib.BuiltinImporter'>, '__spec__': None, '__annotations__': {}, '__builtins__': <module 'builtins' (built-in)>, 'func1': <function func1 at 0x10384c598>}
after func1 local: {'name': 1, 'ayu': 1}
after func1 global: {'__name__': '__main__', '__doc__': None, '__package__': None, '__loader__': <class '_frozen_importlib.BuiltinImporter'>, '__spec__': None, '__annotations__': {}, '__builtins__': <module 'builtins' (built-in)>, 'func1': <function func1 at 0x10384c598>}
after func2 local: {'name': 1, 'func2': <function func1.<locals>.func2 at 0x103855378>}
after func2 global: {'__name__': '__main__', '__doc__': None, '__package__': None, '__loader__': <class '_frozen_importlib.BuiltinImporter'>, '__spec__': None, '__annotations__': {}, '__builtins__': <module 'builtins' (built-in)>, 'func1': <function func1 at 0x10384c598>}
>>> del(func1) #3
>>> locals()
{'__name__': '__main__', '__doc__': None, '__package__': None, '__loader__': <class '_frozen_importlib.BuiltinImporter'>, '__spec__': None, '__annotations__': {}, '__builtins__': <module 'builtins' (built-in)>}
>>> globals()
{'__name__': '__main__', '__doc__': None, '__package__': None, '__loader__': <class '_frozen_importlib.BuiltinImporter'>, '__spec__': None, '__annotations__': {}, '__builtins__': <module 'builtins' (built-in)>}
>>>
以上代碼在命令行中執行，#2中調用完func2之后，#1中的局部命名空間被刪除，執行#3之后，func1中的全局命名空間被刪除，而builtins命名空間需要在退出解釋器后才會被回收
調用
>>> def func1():
... x = 1
... print(x)
... def func2():
... x += x
... print(x)
... func2()
...
>>> func1()
1
Traceback (most recent call last):File "<stdin>", line 1, in <module>File "<stdin>", line 7, in func1File "<stdin>", line 5, in func2
UnboundLocalError: local variable 'x' referenced before assignment
>>>
在執行func2時會報錯，因為執行func2時，會在局部變量中創建x，然后從其局部變量中查找x，始終沒有到Enclosing中取。
參考的博客
由一個例子到python的名字空間
轉載于:https://blog.51cto.com/dorebmoon/2336954
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