To understand how Pandas works with time series, we need to understand the datetime module of Python. The main object types of this module are below

date - stores year, month, day using Gregorian calendar
time - stores hours, minutes, seconds, microseconds
datetime - both date and time
timedelta - difference between two datetime values - represented as days, seconds, microseconds

`datetime` module



In [1]:

    
from datetime import datetime



In [2]:

    
now = datetime.now()
now









    Out[2]:





datetime.datetime(2020, 3, 12, 15, 51, 21, 230960)



In [5]:

    
(now.year, now.month, now.day, now.hour, now.minute)









    Out[5]:





(2020, 3, 12, 15, 51)

Time delta

You can get the time difference between two dates as timedelta objects



In [6]:

    
delta = datetime(2020,3,12) - datetime(2020,9,25)
delta









    Out[6]:





datetime.timedelta(days=-197)



In [8]:

    
(delta.days, delta.seconds)









    Out[8]:





(-197, 0)

Shifting time with `timedelta`



In [9]:

    
from datetime import timedelta



In [12]:

    
datetime.now() + timedelta(days=25)









    Out[12]:





datetime.datetime(2020, 4, 6, 15, 57, 52, 925891)



In [13]:

    
datetime.now() - timedelta(days=20, hours=5)









    Out[13]:





datetime.datetime(2020, 2, 21, 10, 58, 23, 219047)

Working with time stamps



In [16]:

    
stamp = datetime.now()
str(stamp)









    Out[16]:





'2020-03-12 16:07:14.063049'

Printing time stamps



In [24]:

    
stamp.strftime('%Y-%m-%d-%H-%M-%S')









    Out[24]:





'2020-03-12-16-07-14'

The table below gives most popular format strings to use with strftime.

%Y - 4 digit year
%y - 2 digit year
%m - 2 digit month [02,10]
%d - 2 digit day [01,22]
%H - hours in 24 hour clock, 2 digits
%I - hours in 12 hour clock, 2 digits
%M - minutes, 2 digits
%S - seconds, 2 digits
%w - weekday as integer [0 (sun) - 6 (sat)]
%U - week number, 2 digits, from 00-53. First Sunday of the year is the start of the week (1) and days before belong to week 0
%W - week number where Monday is the start of the week
%z - UTC time zone offset as +HHMM or -HHMM, empty is time zone is unknown (naive)
%F - shortcut for %Y-%m-%d (2020-03-12)
%D - shortcut for %m/%d/%y (03/12/20)

If you notice, year, month, date are lower while hour, min, sec are upper cases.



In [28]:

    
datetime.now().strftime('Current hour is %I and week number is %U')









    Out[28]:





'Current hour is 04 and week number is 10'



In [29]:

    
datetime.now().strftime('%z')









    Out[29]:





''



In [30]:

    
datetime.now().strftime('%D')









    Out[30]:





'03/12/20'

Reading timestamps into `datetime` objects using `strptime()`



In [33]:

    
stamp_str = '03/12/20'
datetime.strptime(stamp_str, '%m/%d/%y')









    Out[33]:





datetime.datetime(2020, 3, 12, 0, 0)

Parsing with `dateutil` package

dateutil is a 3rd party package and allows you to parse common date formats without explicitly stating the format.



In [34]:

    
from dateutil.parser import parse



In [35]:

    
parse('03/12/20')









    Out[35]:





datetime.datetime(2020, 3, 12, 0, 0)



In [ ]:

datetime module