datetime weekday() function

[ryanboesch]

BPO	3336
Nosy	@tim-one

^{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 2008-07-16.02:40:35.053>
created_at = <Date 2008-07-10.19:39:41.728>
labels = ['type-bug']
title = 'datetime weekday() function'
updated_at = <Date 2008-07-16.02:40:35.052>
user = 'https://bugs.python.org/ryanboesch'

bugs.python.org fields:

activity = <Date 2008-07-16.02:40:35.052>
actor = 'georg.brandl'
assignee = 'none'
closed = True
closed_date = <Date 2008-07-16.02:40:35.053>
closer = 'georg.brandl'
components = []
creation = <Date 2008-07-10.19:39:41.728>
creator = 'ryanboesch'
dependencies = []
files = []
hgrepos = []
issue_num = 3336
keywords = []
message_count = 2.0
messages = ['69517', '69518']
nosy_count = 2.0
nosy_names = ['tim.peters', 'ryanboesch']
pr_nums = []
priority = 'normal'
resolution = 'wont fix'
stage = None
status = 'closed'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue3336'
versions = ['Python 2.5']

[ryanboesch]

Leap year ignored each century (2100, 2200, 2300, etc.) except 2000 for
the weekday() function. This code reproduces the error:

import datetime
datetime.date(2100,2,29).weekday()

Error message:
ValueError: day is out of range for the month

Also, this causes the weekday to be 1 day off from March 1st, 2100 to
February 28th 2200 and 2 days off...

[tim-one]

The error message is correct. In the Gregorian calendar, years
divisible by 100 are not leap years, unless they're also divisible by
400. So 2000, 2400, 2800, ..., are leap years, but 2100, 2200, 2300,
2500, 2600, 2700, 2900, ... are not leap years. Look it up (anywhere ;-)).