Python布爾邏輯混淆

Question

有人可以澄清這些賦值語句背後的邏輯。

>>> True 
True 
>>> True = False 
>>> True 
False 
>>> True = True 
>>> True 
False 
>>> a = True 
>>> if a: 
...  print "a is True" 
... else: 
...  print "a is False" 
... 
a is False 

根據手冊，類布爾的僅兩個實例是True和False。

Help on bool object: 

True = class bool(int) 
| bool(x) -> bool 
| 
| Returns True when the argument x is true, False otherwise. 
| The builtins True and False are the only two instances of the class bool. 
| The class bool is a subclass of the class int, and cannot be subclassed. 
| 
| Method resolution order: 
|  bool 
|  int 
|  object 

所以我重寫默認實例？如果是這樣，爲什麼python不會將True指定爲下面賦值中的默認實例？我如何在下面的語句中指定默認的python True？

>>> True = False 
>>> True 
False 
>>> True = True 
>>> True 
False  #why? 

在此先感謝您的幫助！

Answer 1

當你這樣做：

True = False 

True成爲False ..當你這樣做：

True = True 

這就像寫：

True = False 

如果你想它「原」True再次，你應該：

>>> True = not True # recall that you assigned False to True 
>>> True 
True