请问Python中d与D的区别在什么地方呢
0
[已解决问题]
解决于 2012-06-01 17:08
# __nonzero__() overridden to return False
class D:
def __nonzero__(self):
return False
d = D()
print '__nonzero__() overridden to return False: ', bool(d)
print '__nonzero__() overridden to return False: ', bool(D)
为什么一个是True， 一个是False？
最佳答案
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object.__nonzero__(self)
Called to implement truth value testing and the built-in operation bool(); should return False or True, or their integer equivalents 0 or 1. When this method is not defined, __len__() is called, if it is defined, and the object is considered true if its result is nonzero. If a class defines neither __len__() nor __nonzero__(), all its instances are considered true.
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其他回答(1)
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谢谢 dudu ，实际上关于__nonzero__和bool的用法我知道一二，最主要想知道，d=D(),这个有什么变化，这里的d和D有什么区别，谢谢