Python 将 0 评估为 False
问题描述
在 Python 控制台中:
In the Python console:
>>> a = 0
>>> if a:
... print "L"
...
>>> a = 1
>>> if a:
... print "L"
...
L
>>> a = 2
>>> if a:
... print "L"
...
L
为什么会这样?
解决方案
在Python中，bool是int的子类，False值为 0；即使值没有在 if 语句(它们是)中隐式转换为 bool，False == 0 也是 true.
In Python, bool is a subclass of int, and False has the value 0; even if values weren't implicitly cast to bool in an if statement (which they are), False == 0 is true.
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