Python - Checking times and dates

$ python
Python 2.7.10 (default, Jul 14 2015, 19:46:27) 
[GCC 4.2.1 Compatible Apple LLVM 6.0 (clang-600.0.39)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> from datetime import datetime
>>> 
>>> print datetime.now()
2016-06-22 12:34:06.719688
>>>

You can also use datetime.today().

>>> print datetime.today()
2016-06-22 14:31:26.736321
>>>

The time is in hours, minutes, seconds, and fractions of a second.

If you just want to see the current date, you can use the following code to extract the date:

>>> from datetime import datetime
>>> print str(datetime.now())[0:10]
2016-06-22
>>>

str(datetime.now()) converts the date and time value to a string. The [0:10] that follows extracts just the first ten characters. Counting of character positions starts with zero so The "2" in "2016" is at position 0 and the second "2" in "2" is at position 9. The [0:10] extracts the characters from position 0 up to, but not including 10.

If you just want the time, you can use the following code:

>>> print str(datetime.now())[11:19]
12:53:32
>>>

Or, if you just want the year, month, or day, you can add .day,.month, or .year as shown below, rather than specifying the character range to extract. E.g.

>>> print datetime.now().day
22
>>> thisday = datetime.now()
>>> print thisday.year
2016
>>> print thisday.month
6
>>> print thisday.day
22

If you need to know the day of the week for a date, e.g., Monday, Tuesday, Wednesday, etc., you can add .weekday.

E.g.:

>>> print datetime.today()
2016-06-22 14:50:44.952305
>>> print datetime.now().weekday()
2
>>> print datetime.now().isoweekday()
3
>>> 
>>> print datetime(2016,06,24).weekday()
4
>>> print datetime(2016,06,24).isoweekday()
5
>>>

There is also a timedelta object in the datetime module. If you import it as well, you can determine a particular date and time that is a certain number of weeks, days, or hours from another date and time. E.g.:

>>> from datetime import datetime, timedelta
>>> print datetime.now()
2016-06-22 13:19:20.196783
>>> print datetime.now() + timedelta(hours=25)
2016-06-23 14:19:43.204564
>>> print datetime.now() + timedelta(days=3)
2016-06-25 13:21:05.377745
>>> print datetime.now() + timedelta(weeks=1)
2016-06-29 13:23:45.572960
>>>

The delta value doesn't have to be a positive value; you can use negative values to determine dates and times in the past. E.g.

>>> print datetime.now()
2016-06-22 13:28:35.924283
>>> print datetime.now() + timedelta(days=-365)
2015-06-23 13:29:20.762302
>>> print datetime.now() + timedelta(hours=-5)
2016-06-22 08:29:39.698231
>>> print datetime.now() + timedelta(weeks=-3)
2016-06-01 13:30:00.193064
>>>

If you want to know how many days have elapsed from a particular day, you can use commands similar to the ones below:

>>> print datetime.now() - datetime(2013,12,31)
904 days, 14:25:26.909957
>>> print datetime(2016,06,22) - datetime(2013,12,31)
904 days, 0:00:00
>>>

You can also of course, use similar commands to determine the number of days between any two dates.

>>> print datetime(2019,4,14) - datetime(2016,8,22)
965 days, 0:00:00
>>> print datetime(2016,8,22) - datetime(2013,12,31)
965 days, 0:00:00

To eliminate the display of hours, minutes, and seconds, the command can be formatted as follows, instead:

>>> print (datetime(2016,06,22) - datetime(2013,12,31)).days
904
>>> print (datetime.now() - datetime(2013,12,31)).days
904
>>>

You can also use Python's strftime directive to format the display of date and time information. E.g., if I wanted to know what date is 1,000 days from December 31, 2013, I could display the date as shown below. In the first case, hours, minutes, and seconds are displayed when I don't apply any formatting control. But, using strftime, I can display only the date plus control how the date is formatted when it is displayed.

>>> days = datetime(2013,12,31) + timedelta(days=1000)
>>> print days
2016-09-26 00:00:00
>>> days.strftime('%m/%d/%Y')
'09/26/2016'
>>> days.strftime('%m/%d/%y')
'09/26/16'
>>> days.strftime('%Y-%m-%d')
'2016-09-26'

The directives used above are as follows (other directives are also available):

I can put slashes or dashes between the parts of the date, depending on how I want it to appear.

Related:

Determining the number of days from or to a given date with Python

 

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