Why do integers compare equal to booleans?
David Raymond
David.Raymond at tomtom.com
Fri Nov 16 10:30:57 EST 2018
A boolean type didn't come about until version 2.3, and even now they still inherit from integers.
Some links for you:
https://docs.python.org/3.7/whatsnew/2.3.html#pep-285-a-boolean-type
https://docs.python.org/3.7/library/stdtypes.html#boolean-values
https://docs.python.org/3.7/reference/datamodel.html#the-standard-type-hierarchy
-----Original Message-----
From: Python-list [mailto:python-list-bounces+david.raymond=tomtom.com at python.org] On Behalf Of Steve Keller
Sent: Friday, November 16, 2018 9:51 AM
To: python-list at python.org
Subject: Why do integers compare equal to booleans?
Why do the integers 0 and 1 compare equal to the boolean values False
and True and all other integers to neither of them?
$ python3
Python 3.5.2 (default, Nov 12 2018, 13:43:14)
[GCC 5.4.0 20160609] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> 0 == False
True
>>> 1 == True
True
>>> 2 == False
False
>>> 2 == True
False
>>> -1 == False
False
>>> -1 == True
False
>>>
Since these are objects of different types I would expect they cannot
be equal. I know that 0 means false and != 0 means true in C, C++,
etc. but in Python that surprises me.
Steve
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