Am 29.10.19 um 01:31 schrieb Changbin Du:
But is it, really? I agree with Jon about the distinction between None
and '' being confusing.
Here python is different from C. Both empty string and None are False in python.
Note such condition is common in python.
The one is a empty string str(''), its bool('') value is False.
| >>> type(''), bool('')
| (<class 'str'>, False)
The other is a NoneType, its bool(None) value is False.
| >>> type(None), bool(None)
| (<class 'NoneType'>, False)
None often used like NULL (pointer). E.g if a function does not give an explicit
return value, the returned value is None.
| >>> def foo():
| ... pass
| ...
| >>> print(foo())
| None
-- Markus --
