all(),any()的矛盾

mihello

1. >>> all([])
   
2. True
   
3. >>> help(all)
   
4. Help on built-in function all in module builtins:
   
5. 
   
6. all(...)
   
7.     all(iterable) -> bool
   
8.    
   
9.     Return True if bool(x) is True for all values x in the iterable.
   
10. 
    
11. >>> any([])
    
12. False
    
13. >>> help(any)
    
14. Help on built-in function any in module builtins:
    
15. 
    
16. any(...)
    
17.     any(iterable) -> bool
    
18.    
    
19.     Return True if bool(x) is True for any x in the iterable.

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空列表的all居然为真，而any为假这个正确。
这为毛了？？求解

darkn3ss

http://stackoverflow.com/questio ... for-empty-iterables

以前还没深究过，这个问题挺好

linux_c_py_php

没有原因, 只有手册:

1. all(iterable)
   
2. Return True if all elements of the iterable are true (or if the iterable is empty). Equivalent to:
   
3. 
   
4. def all(iterable):
   
5.     for element in iterable:
   
6.         if not element:
   
7.             return False
   
8.     return True
   
9. any(iterable)
   
10. Return True if any element of the iterable is true. If the iterable is empty, return False. Equivalent to:
    
11. 
    
12. def any(iterable):
    
13.     for element in iterable:
    
14.         if element:
    
15.             return True
    
16.     return False
    

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