(2,)!=(2) and (2,3)==(2,3,) why ??? tested in each version

[shivaprasanth]

BPO	24901
Nosy	@eryksun

^{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 2015-08-20.11:03:15.981>
created_at = <Date 2015-08-20.10:42:08.971>
labels = ['type-bug', 'invalid']
title = '(2,)!=(2) and (2,3)==(2,3,) why ??? tested in each version'
updated_at = <Date 2015-08-20.11:03:15.948>
user = 'https://bugs.python.org/shivaprasanth'

bugs.python.org fields:

activity = <Date 2015-08-20.11:03:15.948>
actor = 'eryksun'
assignee = 'none'
closed = True
closed_date = <Date 2015-08-20.11:03:15.981>
closer = 'eryksun'
components = []
creation = <Date 2015-08-20.10:42:08.971>
creator = 'shivaprasanth'
dependencies = []
files = []
hgrepos = []
issue_num = 24901
keywords = []
message_count = 2.0
messages = ['248880', '248881']
nosy_count = 1.0
nosy_names = ['eryksun']
pr_nums = []
priority = 'normal'
resolution = 'not a bug'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue24901'
versions = ['Python 2.7', 'Python 3.2', 'Python 3.3', 'Python 3.4']

[shivaprasanth]

Python 2.7.9 (default, Apr  2 2015, 15:33:21) 
[GCC 4.9.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> (2,)==(2)
False
>>> (2,3,)==(2,3)
True
>>> (2,3)==(2,3,)
True
>>> s=(2,)
>>> s2=(2)
>>> s==s2
False
>>>

[eryksun]

Refer to section 6.2.3, parenthesized forms:

https://docs.python.org/3/reference/expressions.html#parenthesized-forms

if the list contains at least one comma, it yields a tuple;
otherwise, it yields the single expression that makes up the
expression list.

So (2) is an int, while (2,) is a tuple that contains an int.

The exception is the empty tuple, for which parentheses are
required — allowing unparenthesized “nothing” in 
expressions would cause ambiguities and allow common typos
to pass uncaught.

Thus () is an empty tuple. Note also that section 6.13 states the following regarding a trailing comma:

The trailing comma is required only to create a single 
tuple (a.k.a. a singleton); it is optional in all other 
cases.