boolean - Python evaluates 0 as False

Question

In the Python console:

>>> a = 0
>>> if a:
...   print "L"
... 
>>> a = 1
>>> if a:
...   print "L"
... 
L
>>> a = 2
>>> if a:
...   print "L"
... 
L

Why does this happen?

Answer 1

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.