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Everything about date & time in python

Posted on 02 Apr, 2021
Earth rotates just like my head trying to understand dates and time-zones.

Get current date & time

>>> import datetime
# without timezone
>>> datetime.datetime.now().strftime("%d %b, %Y (%I:%M:%S %p)")
'02 Apr, 2021 (01:37:43 PM)'
# with local timezone
>>> datetime.datetime.now(datetime.timezone.utc).astimezone().strftime("%d %b, %Y (%I:%M:%S %p) %Z")
'02 Apr, 2021 (01:38:20 PM) IST'

Current date/time to Unix timestamp

>>> import time
>>> t = datetime.datetime.now(datetime.timezone.utc).astimezone()
>>> t.timetuple()
time.struct_time(tm_year=2021, tm_mon=4, tm_mday=2, tm_hour=13, tm_min=43, tm_sec=15, tm_wday=4, tm_yday=92, tm_isdst=-1)
>>> time.mktime(t.timetuple())
1617351195.0

Unix timestamp to date/time

>>> import time
>>> t = datetime.datetime.now(datetime.timezone.utc).astimezone()
>>> unix_t = time.mktime(t.timetuple())
1617351195.0
>>> t = time.localtime(unix_t)
time.struct_time(tm_year=2021, tm_mon=4, tm_mday=2, tm_hour=13, tm_min=46, tm_sec=32, tm_wday=4, tm_yday=92, tm_isdst=0)
# verify
>>> time.strftime("%d %b, %Y (%I:%M:%S %p)", t)
'02 Apr, 2021 (01:46:32 PM IST)'

datetime object to string

>>> from datetime import datetime
>>> d = datetime.now()
>>> d
datetime.datetime(2020, 11, 7, 20, 15, 58, 389341)
>>> d.strftime("%d %b, %Y")
'07 Nov, 2020'

From string to datetime object

>>> from datetime import datetime
>>> date_string = "2020-06-20T08:22:54Z"
>>> datetime.strptime(date_string, '%Y-%m-%dT%H:%M:%SZ')
datetime.datetime(2020, 6, 20, 8, 22, 54)
Both strptime & strftime can ofc be chained.
>>> from datetime import datetime
>>> date_string = "2020-06-20T08:22:54Z"
>>> datetime.strptime(date_string, '%Y-%m-%dT%H:%M:%SZ').strftime("%d %b, %Y")
This can be handy when you are getting date/time fields from external resource (like an API) and only want to display a part of it (like days, month etc).
Directive
Meaning
Example
%a
Weekday as locale’s abbreviated name.
Sun, Mon, …, Sat (en_US);So, Mo, …, Sa (de_DE)
%A
Weekday as locale’s full name.
Sunday, Monday, …, Saturday (en_US);Sonntag, Montag, …, Samstag (de_DE)
%w
Weekday as a decimal number, where 0 is Sunday and 6 is Saturday.
0, 1, …, 6
%d
Day of the month as a zero-padded decimal number.
01, 02, …, 31
%b
Month as locale’s abbreviated name.
Jan, Feb, …, Dec (en_US);Jan, Feb, …, Dez (de_DE)
%B
Month as locale’s full name.
January, February, …, December (en_US);Januar, Februar, …, Dezember (de_DE)
%m
Month as a zero-padded decimal number.
01, 02, …, 12
%y
Year without century as a zero-padded decimal number.
00, 01, …, 99
%Y
Year with century as a decimal number.
0001, 0002, …, 2013, 2014, …, 9998, 9999
%H
Hour (24-hour clock) as a zero-padded decimal number.
00, 01, …, 23
%I
Hour (12-hour clock) as a zero-padded decimal number.
01, 02, …, 12
%p
Locale’s equivalent of either AM or PM.
AM, PM (en_US);am, pm (de_DE)
%M
Minute as a zero-padded decimal number.
00, 01, …, 59
%S
Second as a zero-padded decimal number.
00, 01, …, 59
%f
Microsecond as a decimal number, zero-padded on the left.
000000, 000001, …, 999999
%z
UTC offset in the form ±HHMM[SS[.ffffff]] (empty string if the object is naive).
(empty), +0000, -0400, +1030, +063415, -030712.345216
%Z
Time zone name (empty string if the object is naive).
(empty), UTC, GMT
%j
Day of the year as a zero-padded decimal number.
001, 002, …, 366
%U
Week number of the year (Sunday as the first day of the week) as a zero padded decimal number. All days in a new year preceding the first Sunday are considered to be in week 0.
00, 01, …, 53
%W
Week number of the year (Monday as the first day of the week) as a decimal number. All days in a new year preceding the first Monday are considered to be in week 0.
00, 01, …, 53
%c
Locale’s appropriate date and time representation.
Tue Aug 16 21:30:00 1988 (en_US);Di 16 Aug 21:30:00 1988 (de_DE)
%x
Locale’s appropriate date representation.
08/16/88 (None);08/16/1988 (en_US);16.08.1988 (de_DE)
%X
Locale’s appropriate time representation.
21:30:00 (en_US);21:30:00 (de_DE)
%%
A literal '%' character.
%