bool variable isinstance of int

[noobie1000]

BPO	45891
Nosy	@tiran, @stevendaprano

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = <Date 2021-11-24.14:30:23.502>
created_at = <Date 2021-11-24.13:04:10.797>
labels = ['type-bug', 'expert-IO']
title = 'bool variable isinstance of int'
updated_at = <Date 2021-11-24.14:30:23.502>
user = 'https://bugs.python.org/noobie1000'

bugs.python.org fields:

activity = <Date 2021-11-24.14:30:23.502>
actor = 'noobie1000'
assignee = 'none'
closed = True
closed_date = <Date 2021-11-24.14:30:23.502>
closer = 'noobie1000'
components = ['IO']
creation = <Date 2021-11-24.13:04:10.797>
creator = 'noobie1000'
dependencies = []
files = []
hgrepos = []
issue_num = 45891
keywords = []
message_count = 4.0
messages = ['406926', '406929', '406932', '406933']
nosy_count = 3.0
nosy_names = ['christian.heimes', 'steven.daprano', 'noobie1000']
pr_nums = []
priority = 'normal'
resolution = None
stage = 'resolved'
status = 'closed'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue45891'
versions = ['Python 3.6']

[noobie1000]

Hello,

Recently I observed that isinstance(x, int) returns True, even when x is defined as a bool. While I understand that internally, a bool is treated as an int with values 0 and 1; to me, this is a bit misleading that the python interpreter returns True when we perform the isinstance() check. May be I'm missing some deeper explanation. Could someone please shed some light on this. Has this been discussed by the community in the past. Thank you very much for reading this ticket.

>>> x = True
>>> isinstance(x, int)
True

[tiran]

This is the expected behavior. The bool type is a subtype of int. True is int 1 in disguise and False is int 0.

>>> bool.__mro__
(<class 'bool'>, <class 'int'>, <class 'object'>)

>>> True == 1
True
>>> True == 2
False

>>> False == 0
True

[stevendaprano]

Hi noobie1000,

This is not a general forum for asking questions about Python's design or language, this is for reporting bugs.

There are many forums where you can ask "Why" questions and ask for the community to "shed some light on this", such as Reddit's r/python, the various mailing lists, Discuss, IRC, etc. In future please use them rather than the bug tracker.

Regarding bool, you can start by reading this:

https://www.python.org/dev/peps/pep-0285/

If that doesn't answer your questions, please feel free to take them to the many different forums here:

https://www.python.org/community/forums/

https://www.python.org/community/lists/

https://www.python.org/community/irc/

[noobie1000]

Hello Steven,

Sorry, this is my first ever post and was lost in the enormity of issues/documentation. Noted your points :)

Thank you.