Python Datetime Tutorial: Manipulate Times, Dates, and Time Spans

By Avinash Navlani · Updated January 5, 2026

Originally published October 31, 2019

Dealing with dates and times in Python can be a hassle. Thankfully, there’s a built-in way of making it easier: the Python datetime module.

datetime helps us identify and process time-related elements like dates, hours, minutes, seconds, days of the week, months, years, etc. It offers various services like managing time zones and daylight savings time. It can work with timestamp data. It can extract the day of the week, day of the month, and other date and time formats from strings.

In short, it’s a really powerful way of handling anything date and time related in Python. So let’s get into it!

In this tutorial, we’ll learn about python datetime functions in detail, including:

• Creating Date Objects
• Getting year and month from the date
• Getting month day and Weekday from date
• Getting hour and minutes from the date
• Getting Week number of the year from date
• Converting date object into timestamp
• Converting UNIX timestamp string to date object
• Handling timedelta objects
• Getting the difference between two dates and times
• Formatting dates: strftime() and strptime()
• Handling timezones
• Working with Pandas datetime objects
  • Getting year, month, day, hour, and minute
  • Getting weekday and day of year
  • Converting date objects into a DataFrame index

As you work through this tutorial, we’d encourage you to run the code on your own machine. Alternatively, if you’d like to run code in your browser and learn in an interactive fashion with answer-checking to be sure you’re getting it right, our Python intermediate course has a lesson on datetime in Python that we recommend. You can start learning by signing up for a free user account.

Python datetime Classes

Before jumping into writing code, it’s worth looking at the five main object classes that are used in the datetime module. Depending on what we’re trying to do, we’ll likely need to make use of one or more of these distinct classes:

• datetime – Allows us to manipulate times and dates together (month, day, year, hour, second, microsecond).
• date – Allows us to manipulate dates independent of time (month, day, year).
• time – Allows us to manipulate time independent of date (hour, minute, second, microsecond).
• timedelta— A duration of time used for manipulating dates and measuring.
• tzinfo— An abstract class for dealing with time zones.

If those distinctions don’t make sense yet, don’t worry! Let’s dive into datetime and start working with it to better understand how these are applied.

Creating Date Objects

First, let’s take a closer look at a datetime object. Since datetime is both a module and a class within that module, we’ll start by importing the datetime class from the datetime module.

Then, we’ll print the current date and time to take a closer look at what’s contained in a datetime object. We can do this using datetime‘s .now() function. We’ll print our datetime object, and then also print its type using type() so we can take a closer look.

<span class="token comment" spellcheck="true"># import datetime class from datetime module</span>
<span class="token keyword">from</span> datetime <span class="token keyword">import</span> datetime

<span class="token comment" spellcheck="true"># get current date</span>
datetime_object <span class="token operator">=</span> datetime<span class="token punctuation">.</span>now<span class="token punctuation">(</span><span class="token punctuation">)</span>
<span class="token keyword">print</span><span class="token punctuation">(</span>datetime_object<span class="token punctuation">)</span>
<span class="token keyword">print</span><span class="token punctuation">(</span><span class="token string">'Type :- '</span><span class="token punctuation">,</span>type<span class="token punctuation">(</span>datetime_object<span class="token punctuation">)</span><span class="token punctuation">)</span>

2019-10-25 10:24:01.521881
Type :-  'datetime.datetime'

We can see from the results above that datetime_object is indeed a datetime object of the datetime class. This includes the year, month, day, hour, minute, second, and microsecond.

Extract Year and Month from the Date

Now we’ve seen what makes up a datetime object, we can probably guess how date and time objects look, because we know that date objects are just like datetime without the time data, and time objects are just like datetime without the date data.

We can also antipate some problems. For example, in most data sets, date and time information is stored in string format! Also, we may not want all of this date and time data — if we’re doing something like a monthly sales analysis, breaking things down by microsecond isn’t going to be very useful.

So now, let’s start digging into a common task in data science: extracting only the elements that we actually want from a string using datetime.

To do this, we need to do a few things.

Handling Date and Time Strings with strptime() and strftime()

Thankfully, datetime includes two methods, strptime() and strftime(), for converting objects from strings to datetime objects and vice versa. strptime() can read strings with date and time information and convert them to datetime objects, and strftime() converts datetime objects back into strings.

Of course, strptime() isn’t magic — it can’t turn any string into a date and time, and it will need a little help from us to interpret what it’s seeing! But it’s capable of reading most conventional string formats for date and time data (see the documentation for more details). Let’s give it a date string in YYYY-MM-DD format and see what it can do!

my_string <span class="token operator">=</span> <span class="token string">'2019-10-31'</span>

<span class="token comment" spellcheck="true"># Create date object in given time format yyyy-mm-dd</span>
my_date <span class="token operator">=</span> datetime<span class="token punctuation">.</span>strptime<span class="token punctuation">(</span>my_string<span class="token punctuation">,</span> <span class="token string">"\%Y-\%m-\%d"</span><span class="token punctuation">)</span>

<span class="token keyword">print</span><span class="token punctuation">(</span>my_date<span class="token punctuation">)</span>
<span class="token keyword">print</span><span class="token punctuation">(</span><span class="token string">'Type: '</span><span class="token punctuation">,</span>type<span class="token punctuation">(</span>my_date<span class="token punctuation">)</span><span class="token punctuation">)</span>

2019-10-31 00:00:00 Type:  'datetime.datetime'

Note that strptime() took two arguments: the string (my_string) and "\%Y-\%m-\%d", another string that tells strptime() how to interpret the input string my_string. \%Y, for example, tells it to expect the first four characters of the string to be the year.

A full list of these patterns is available in the documentation, and we’ll go into these methods in more depth later in this tutorial.

You may also have noticed that a time of 00:00:00 has been added to the date. That’s because we created a datetime object, which must include a date and a time. 00:00:00 is the default time that will be assigned if no time is designated in the string we’re inputting.

Anyway, we were hoping to separate out specific elements of the date for our analysis. One way can do that using the built-in class attributes of a datetime object, like .month or .year:

<span class="token keyword">print</span><span class="token punctuation">(</span><span class="token string">'Month: '</span><span class="token punctuation">,</span> my_date<span class="token punctuation">.</span>month<span class="token punctuation">)</span> <span class="token comment" spellcheck="true"># To Get month from date</span>
<span class="token keyword">print</span><span class="token punctuation">(</span><span class="token string">'Year: '</span><span class="token punctuation">,</span> my_date<span class="token punctuation">.</span>year<span class="token punctuation">)</span> <span class="token comment" spellcheck="true"># To Get month from year</span>

Month:  10 Year:  2019

Getting Day of the Month and Day of the Week from a Date

Let’s do some more extraction, because that’s a really common task. This time, we’ll try to get the day of the month and the day of the week from my_date. Datetime will give us the day of the week as a number using its .weekday() function, but we can convert this to a text format (i.e. Monday, Tuesday, Wednesday…) using the calendar module and a method called day_name.

We’ll start by importing calendar, and then using .day and .weekday() on my_date. From there, we can get the day of the week in text format like so:

<span class="token comment" spellcheck="true"># import calendar module</span>
<span class="token keyword">import</span> calendar
<span class="token keyword">print</span><span class="token punctuation">(</span><span class="token string">'Day of Month:'</span><span class="token punctuation">,</span> my_date<span class="token punctuation">.</span>day<span class="token punctuation">)</span>

<span class="token comment" spellcheck="true"># to get name of day(in number) from date</span>
<span class="token keyword">print</span><span class="token punctuation">(</span><span class="token string">'Day of Week (number): '</span><span class="token punctuation">,</span> my_date<span class="token punctuation">.</span>weekday<span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span>

<span class="token comment" spellcheck="true"># to get name of day from date</span>
<span class="token keyword">print</span><span class="token punctuation">(</span><span class="token string">'Day of Week (name): '</span><span class="token punctuation">,</span> calendar<span class="token punctuation">.</span>day_name<span class="token punctuation">[</span>my_date<span class="token punctuation">.</span>weekday<span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">]</span><span class="token punctuation">)</span>

Day of Month: 31 Day of Week (number):  3 Day of Week (name):  Thursday

Wait a minute, that looks a bit odd! The third day of the week should be Wednesday, not Thursday, right?

Let’s take a closer look at that day_name variable using a for loop:

j <span class="token operator">=</span> <span class="token number">0</span>
<span class="token keyword">for</span> i <span class="token keyword">in</span> calendar<span class="token punctuation">.</span>day_name<span class="token punctuation">:</span>
    <span class="token keyword">print</span><span class="token punctuation">(</span>j<span class="token punctuation">,</span><span class="token string">'-'</span><span class="token punctuation">,</span>i<span class="token punctuation">)</span>
    j<span class="token operator">+=</span><span class="token number">1</span>

0 - Monday 1 - Tuesday 2 - Wednesday 3 - Thursday 4 - Friday 5 - Saturday 6 - Sunday

Now we can see that Python starts weeks on Monday and counts from the index 0 rather than starting at 1. So it makes sense that the number 3 is converted to “Thursday” as we saw above.

Getting Hours and Minutes From a Python Datetime Object

Now let’s dig into time and extract the hours and minutes from datetime object. Much like what we did above with month and year, we can use class attributes .hour and .minute to get the hours and minutes of the day.

Let’s set a new date and time using the .now() function. As of this writing, it’s October 25, 2019 at 10:25 AM. You’ll get different results depending on when you choose to run this code, of course!

<span class="token keyword">from</span> datetime <span class="token keyword">import</span> datetime todays_date <span class="token operator">=</span> datetime<span class="token punctuation">.</span>now<span class="token punctuation">(</span><span class="token punctuation">)</span>

<span class="token comment" spellcheck="true"># to get hour from datetime</span>
<span class="token keyword">print</span><span class="token punctuation">(</span><span class="token string">'Hour: '</span><span class="token punctuation">,</span> todays_date<span class="token punctuation">.</span>hour<span class="token punctuation">)</span>

<span class="token comment" spellcheck="true"># to get minute from datetime</span>
<span class="token keyword">print</span><span class="token punctuation">(</span><span class="token string">'Minute: '</span><span class="token punctuation">,</span> todays_date<span class="token punctuation">.</span>minute<span class="token punctuation">)</span>

Hour:  10 Minute:  25

Getting Week of the Year from a Datetime Object

We can also do fancier things with datetime. For example, what if we want to know what week of the year it is?

We can get the year, week of the year, and day of the week from a datetime object with the .isocalendar() function.

Specifically, isocalendar() returns a tuple with ISO year, week number and weekday. The ISO calendar is a widely-used standard calendar based on the Gregorian calendar. You can read about it in more detail at that link, but for our purposes, all we need to know is that it works as a regular calendar, starting each week on Monday.

<span class="token comment" spellcheck="true"># Return a 3-tuple, (ISO year, ISO week number, ISO weekday).</span>
todays_date<span class="token punctuation">.</span>isocalendar<span class="token punctuation">(</span><span class="token punctuation">)</span>

(2019, 43, 5)

Note that in the ISO calendar, the week starts counting from 1, so here 5 represents the correct day of the week: Friday.

We can see from the above that this is the 43rd week of the year, but if we wanted to isolate that number, we could do so with indexing just as we might for any other Python list or tuple:

todays_date.isocalendar()[1]

43

Converting a Date Object into Unix Timestamp and Vice Versa

In programming, it’s not uncommon to encounter time and date data that’s stored as a timestamp, or to want to store your own data in Unix timestamp format.

We can do that using datetime’s built-in timestamp() function, which takes a datetime object as an argument and returns that date and time in timestamp format:

<span class="token comment" spellcheck="true">#import datetime</span>
<span class="token keyword">from</span> datetime <span class="token keyword">import</span> datetime
<span class="token comment" spellcheck="true"># get current date</span>
now <span class="token operator">=</span> datetime<span class="token punctuation">.</span>now<span class="token punctuation">(</span><span class="token punctuation">)</span>

<span class="token comment" spellcheck="true"># convert current date into timestamp</span>
timestamp <span class="token operator">=</span> datetime<span class="token punctuation">.</span>timestamp<span class="token punctuation">(</span>now<span class="token punctuation">)</span>

<span class="token keyword">print</span><span class="token punctuation">(</span><span class="token string">"Date and Time :"</span><span class="token punctuation">,</span> now<span class="token punctuation">)</span>
<span class="token keyword">print</span><span class="token punctuation">(</span><span class="token string">"Timestamp:"</span><span class="token punctuation">,</span> timestamp<span class="token punctuation">)</span>

Date and Time : 2019-10-25 10:36:32.827300 Timestamp: 1572014192.8273

Similarly, we can do the reverse conversion using fromtimestamp(). This is a datetime function that takes a timestamp (in float format) as an argument and returns a datetime object, as below:

<span class="token comment" spellcheck="true">#import datetime</span>
<span class="token keyword">from</span> datetime <span class="token keyword">import</span> datetime
timestamp <span class="token operator">=</span> <span class="token number">1572014192.8273</span>

<span class="token comment" spellcheck="true">#convert timestamp to datetime object</span>
dt_object <span class="token operator">=</span> datetime<span class="token punctuation">.</span>fromtimestamp<span class="token punctuation">(</span>timestamp<span class="token punctuation">)</span>

<span class="token keyword">print</span><span class="token punctuation">(</span><span class="token string">"dt_object:"</span><span class="token punctuation">,</span> dt_object<span class="token punctuation">)</span>
<span class="token keyword">print</span><span class="token punctuation">(</span><span class="token string">"type(dt_object): "</span><span class="token punctuation">,</span> type<span class="token punctuation">(</span>dt_object<span class="token punctuation">)</span><span class="token punctuation">)</span>

dt_object: 2019-10-25 10:36:32.827300 type(dt_object):  <class 'datetime.datetime'>

Measuring Time Span with Timedelta Objects

Often, we may want to measure a span of time, or a duration, using Python datetime. We can do this with its built-in timedelta class. A timedelta object represents the amount of time between two dates or times. We can use this to measure time spans, or manipulate dates or times by adding and subtracting from them, etc.

By default a timedelta object has all parameters set to zero. Let’s create a new timedelta object that’s two weeks long and see how that looks:

<span class="token comment" spellcheck="true">#import datetime</span>
<span class="token keyword">from</span> datetime <span class="token keyword">import</span> timedelta
<span class="token comment" spellcheck="true"># create timedelta object with difference of 2 weeks</span>
d <span class="token operator">=</span> timedelta<span class="token punctuation">(</span>weeks<span class="token operator">=</span><span class="token number">2</span><span class="token punctuation">)</span>

<span class="token keyword">print</span><span class="token punctuation">(</span>d<span class="token punctuation">)</span>
<span class="token keyword">print</span><span class="token punctuation">(</span>type<span class="token punctuation">(</span>d<span class="token punctuation">)</span><span class="token punctuation">)</span>
<span class="token keyword">print</span><span class="token punctuation">(</span>d<span class="token punctuation">.</span>days<span class="token punctuation">)</span>

14 days, 0:00:00 <class 'datetime.timedelta'> 14

Note that we can get our time duration in days by using the timedelta class attribute .days. As we can see in its documentation, we can also get this time duration in seconds or microseconds.

Let’s create another timedelta duration to get a bit more practice:

year <span class="token operator">=</span> timedelta<span class="token punctuation">(</span>days<span class="token operator">=</span><span class="token number">365</span><span class="token punctuation">)</span>
<span class="token keyword">print</span><span class="token punctuation">(</span>year<span class="token punctuation">)</span>

365 days, 0:00:00

Now let’s start doing using timedelta objects together with datetime objects to do some math! Specifically, let’s add a few diffeent time durations to the current time and date to see what date it will be after 15 days, what date it was two weeks ago.

To do this, we can use the + or - operators to add or subtract the timedelta object to/from a datetime object. The result will be the datetime object plus or minus the duration of time specified in our timedelta object. Cool, right?

(Note: in the code below, it’s October 25 at 11:12 AM; your results will differ depending on when you run the code since we’re getting our datetime object using the .now() function).

<span class="token comment" spellcheck="true">#import datetime</span>
<span class="token keyword">from</span> datetime <span class="token keyword">import</span> datetime<span class="token punctuation">,</span> timedelta
<span class="token comment" spellcheck="true"># get current time</span>
now <span class="token operator">=</span> datetime<span class="token punctuation">.</span>now<span class="token punctuation">(</span><span class="token punctuation">)</span>
<span class="token keyword">print</span> <span class="token punctuation">(</span><span class="token string">"Today's date: "</span><span class="token punctuation">,</span> str<span class="token punctuation">(</span>now<span class="token punctuation">)</span><span class="token punctuation">)</span>

<span class="token comment" spellcheck="true">#add 15 days to current date</span>
future_date_after_15days <span class="token operator">=</span> now <span class="token operator">+</span> timedelta<span class="token punctuation">(</span>days <span class="token operator">=</span> <span class="token number">15</span><span class="token punctuation">)</span>
<span class="token keyword">print</span><span class="token punctuation">(</span><span class="token string">'Date after 15 days: '</span><span class="token punctuation">,</span> future_date_after_15days<span class="token punctuation">)</span>

<span class="token comment" spellcheck="true">#subtract 2 weeks from current date</span>
two_weeks_ago <span class="token operator">=</span> now <span class="token operator">-</span> timedelta<span class="token punctuation">(</span>weeks <span class="token operator">=</span> <span class="token number">2</span><span class="token punctuation">)</span>
<span class="token keyword">print</span><span class="token punctuation">(</span><span class="token string">'Date two weeks ago: '</span><span class="token punctuation">,</span> two_weeks_ago<span class="token punctuation">)</span>
<span class="token keyword">print</span><span class="token punctuation">(</span><span class="token string">'two_weeks_ago object type: '</span><span class="token punctuation">,</span> type<span class="token punctuation">(</span>two_weeks_ago<span class="token punctuation">)</span><span class="token punctuation">)</span>

Today's date:  2019-10-25 11:12:24.863308 Date after 15 days:  2019-11-09 11:12:24.863308 Date two weeks ago:  2019-10-11 11:12:24.863308 two_weeks_ago object type:  <class 'datetime.datetime'>

Note that the output of these mathematical operations is still a datetime object.

Find the Difference Between Two Dates and Times

Similar to what we did above, we can also subtract one date from another date to find the timespan between them using datetime.

Because the result of this math is a duration, the object produced when we subtract one date from another will be a timedelta object.

Here, we’ll create two date objects (remeber, these work the same as datetime objects, they just don’t include time data) and subtract one from the other to find the duration:

<span class="token comment" spellcheck="true"># import datetime</span>
<span class="token keyword">from</span> datetime <span class="token keyword">import</span> date
<span class="token comment" spellcheck="true"># Create two dates</span>
date1 <span class="token operator">=</span> date<span class="token punctuation">(</span><span class="token number">2008</span><span class="token punctuation">,</span> <span class="token number">8</span><span class="token punctuation">,</span> <span class="token number">18</span><span class="token punctuation">)</span>
date2 <span class="token operator">=</span> date<span class="token punctuation">(</span><span class="token number">2008</span><span class="token punctuation">,</span> <span class="token number">8</span><span class="token punctuation">,</span> <span class="token number">10</span><span class="token punctuation">)</span>

<span class="token comment" spellcheck="true"># Difference between two dates</span>
delta <span class="token operator">=</span> date2 <span class="token operator">-</span> date1
<span class="token keyword">print</span><span class="token punctuation">(</span><span class="token string">"Difference: "</span><span class="token punctuation">,</span> delta<span class="token punctuation">.</span>days<span class="token punctuation">)</span>
<span class="token keyword">print</span><span class="token punctuation">(</span><span class="token string">'delta object type: '</span><span class="token punctuation">,</span> type<span class="token punctuation">(</span>delta<span class="token punctuation">)</span><span class="token punctuation">)</span>

Difference:  -8 delta object type:  <class 'datetime.timedelta'>

Above, we used only dates for the sake of clarity, but we can do the same thing with datetime objects to get a more precise measurement that includes hours, minutes, and seconds as well:

<span class="token comment" spellcheck="true"># import datetime</span>
<span class="token keyword">from</span> datetime <span class="token keyword">import</span> datetime
<span class="token comment" spellcheck="true"># create two dates with year, month, day, hour, minute, and second</span>
date1 <span class="token operator">=</span> datetime<span class="token punctuation">(</span><span class="token number">2017</span><span class="token punctuation">,</span> <span class="token number">6</span><span class="token punctuation">,</span> <span class="token number">21</span><span class="token punctuation">,</span> <span class="token number">18</span><span class="token punctuation">,</span> <span class="token number">25</span><span class="token punctuation">,</span> <span class="token number">30</span><span class="token punctuation">)</span>
date2 <span class="token operator">=</span> datetime<span class="token punctuation">(</span><span class="token number">2017</span><span class="token punctuation">,</span> <span class="token number">5</span><span class="token punctuation">,</span> <span class="token number">16</span><span class="token punctuation">,</span> <span class="token number">8</span><span class="token punctuation">,</span> <span class="token number">21</span><span class="token punctuation">,</span> <span class="token number">10</span><span class="token punctuation">)</span>

<span class="token comment" spellcheck="true"># Difference between two dates</span>
diff <span class="token operator">=</span> date1<span class="token operator">-</span>date2
<span class="token keyword">print</span><span class="token punctuation">(</span><span class="token string">"Difference: "</span><span class="token punctuation">,</span> diff<span class="token punctuation">)</span>

Difference:  36 days, 10:04:20

Formatting Dates: More on strftime() and strptime()

We touched briefly on strftime() and strptime() earlier, but let’s take a closer look at these methods, as they’re often important for data analysis work in Python.

strptime() is the method we used before, and you’ll recall that it can turn a date and time that’s formatted as a text string into a datetime object, in the following format:

time.strptime(string, format)

Note that it takes two arguments:

• string − the time in string format that we want to convert
• format − the specific formatting of the time in the string, so that strptime() can parse it correctly

Let’s try converting a different kind of date string this time. This site is a really useful reference for finding the formatting codes needed to help strptime() interpret our string input.

<span class="token comment" spellcheck="true"># import datetime</span>
<span class="token keyword">from</span> datetime <span class="token keyword">import</span> datetime
date_string <span class="token operator">=</span> <span class="token string">"1 August, 2019"</span>

<span class="token comment" spellcheck="true"># format date</span>
date_object <span class="token operator">=</span> datetime<span class="token punctuation">.</span>strptime<span class="token punctuation">(</span>date_string<span class="token punctuation">,</span> <span class="token string">"\%d \%B, \%Y"</span><span class="token punctuation">)</span>

<span class="token keyword">print</span><span class="token punctuation">(</span><span class="token string">"date_object: "</span><span class="token punctuation">,</span> date_object<span class="token punctuation">)</span>

date_object:  2019-08-01 00:00:00

Now let’s do something a bit more advanced to practice everything we’ve learned so far! We’ll start with a date in string format, convert it to a datetime object, and look at a couple different ways of formatting it (dd/mm and mm/dd).

Then, sticking with the mm/dd formatting, we’ll convert it into a Unix timestamp. Then we’ll convert it back into a datetime object, and convert that back into strings using a few different strftime patterns to control the output:

<span class="token comment" spellcheck="true"># import datetime</span>
<span class="token keyword">from</span> datetime <span class="token keyword">import</span> datetime
dt_string <span class="token operator">=</span> <span class="token string">"12/11/2018 09:15:32"</span>
<span class="token comment" spellcheck="true"># Considering date is in dd/mm/yyyy format</span>
dt_object1 <span class="token operator">=</span> datetime<span class="token punctuation">.</span>strptime<span class="token punctuation">(</span>dt_string<span class="token punctuation">,</span> <span class="token string">"\%d/\%m/\%Y \%H:\%M:\%S"</span><span class="token punctuation">)</span>
<span class="token keyword">print</span><span class="token punctuation">(</span><span class="token string">"dt_object1:"</span><span class="token punctuation">,</span> dt_object1<span class="token punctuation">)</span>
<span class="token comment" spellcheck="true"># Considering date is in mm/dd/yyyy format</span>
dt_object2 <span class="token operator">=</span> datetime<span class="token punctuation">.</span>strptime<span class="token punctuation">(</span>dt_string<span class="token punctuation">,</span> <span class="token string">"\%m/\%d/\%Y \%H:\%M:\%S"</span><span class="token punctuation">)</span>
<span class="token keyword">print</span><span class="token punctuation">(</span><span class="token string">"dt_object2:"</span><span class="token punctuation">,</span> dt_object2<span class="token punctuation">)</span>

<span class="token comment" spellcheck="true"># Convert dt_object2 to Unix Timestamp</span>
timestamp <span class="token operator">=</span> datetime<span class="token punctuation">.</span>timestamp<span class="token punctuation">(</span>dt_object2<span class="token punctuation">)</span>
<span class="token keyword">print</span><span class="token punctuation">(</span><span class="token string">'Unix Timestamp: '</span><span class="token punctuation">,</span> timestamp<span class="token punctuation">)</span>

<span class="token comment" spellcheck="true"># Convert back into datetime</span>
date_time <span class="token operator">=</span> datetime<span class="token punctuation">.</span>fromtimestamp<span class="token punctuation">(</span>timestamp<span class="token punctuation">)</span>
d <span class="token operator">=</span> date_time<span class="token punctuation">.</span>strftime<span class="token punctuation">(</span><span class="token string">"\%c"</span><span class="token punctuation">)</span>
<span class="token keyword">print</span><span class="token punctuation">(</span><span class="token string">"Output 1:"</span><span class="token punctuation">,</span> d<span class="token punctuation">)</span>
d <span class="token operator">=</span> date_time<span class="token punctuation">.</span>strftime<span class="token punctuation">(</span><span class="token string">"\%x"</span><span class="token punctuation">)</span>
<span class="token keyword">print</span><span class="token punctuation">(</span><span class="token string">"Output 2:"</span><span class="token punctuation">,</span> d<span class="token punctuation">)</span>
d <span class="token operator">=</span> date_time<span class="token punctuation">.</span>strftime<span class="token punctuation">(</span><span class="token string">"\%X"</span><span class="token punctuation">)</span>
<span class="token keyword">print</span><span class="token punctuation">(</span><span class="token string">"Output 3:"</span><span class="token punctuation">,</span> d<span class="token punctuation">)</span>

dt_object1: 2018-11-12 09:15:32 
dt_object2: 2018-12-11 09:15:32 
Unix Timestamp:  1544537732.0 
Output 1: Tue Dec 11 09:15:32 2018 
Output 2: 12/11/18 
Output 3: 09:15:32

Here’s an image you can save with a cheat sheet for common, useful strptime and strftime patterns:

Let’s get a little more practice using these:

<span class="token comment" spellcheck="true"># current date and time</span>
now <span class="token operator">=</span> datetime<span class="token punctuation">.</span>now<span class="token punctuation">(</span><span class="token punctuation">)</span>

<span class="token comment" spellcheck="true"># get year from date</span>
year <span class="token operator">=</span> now<span class="token punctuation">.</span>strftime<span class="token punctuation">(</span><span class="token string">"\%Y"</span><span class="token punctuation">)</span>
<span class="token keyword">print</span><span class="token punctuation">(</span><span class="token string">"Year:"</span><span class="token punctuation">,</span> year<span class="token punctuation">)</span>

<span class="token comment" spellcheck="true"># get month from date</span>
month <span class="token operator">=</span> now<span class="token punctuation">.</span>strftime<span class="token punctuation">(</span><span class="token string">"\%m"</span><span class="token punctuation">)</span>
<span class="token keyword">print</span><span class="token punctuation">(</span><span class="token string">"Month;"</span><span class="token punctuation">,</span> month<span class="token punctuation">)</span>

<span class="token comment" spellcheck="true"># get day from date</span>
day <span class="token operator">=</span> now<span class="token punctuation">.</span>strftime<span class="token punctuation">(</span><span class="token string">"\%d"</span><span class="token punctuation">)</span>
<span class="token keyword">print</span><span class="token punctuation">(</span><span class="token string">"Day:"</span><span class="token punctuation">,</span> day<span class="token punctuation">)</span>

<span class="token comment" spellcheck="true"># format time in HH:MM:SS</span>
time <span class="token operator">=</span> now<span class="token punctuation">.</span>strftime<span class="token punctuation">(</span><span class="token string">"%H:%M:%S"</span><span class="token punctuation">)</span>
<span class="token keyword">print</span><span class="token punctuation">(</span><span class="token string">"Time:"</span><span class="token punctuation">,</span> time<span class="token punctuation">)</span>

<span class="token comment" spellcheck="true"># format date</span>
date_time <span class="token operator">=</span> now<span class="token punctuation">.</span>strftime<span class="token punctuation">(</span><span class="token string">"\%m/\%d/\%Y, \%H:\%M:\%S"</span><span class="token punctuation">)</span>
<span class="token keyword">print</span><span class="token punctuation">(</span><span class="token string">"Date and Time:"</span><span class="token punctuation">,</span>date_time<span class="token punctuation">)</span>

Year: 2019 
Month; 10 
Day: 25 
Time: 11:56:41 
Date and Time: 10/25/2019, 11:56:41

Handling Timezones

Working with dates and times in Pythin can get even more complicated when timezones get involved. Thankfully, the pytz module exists to help us deal with cross-timezone conversions. It also handles the daylight savings time in locations that use that.

We can use the localize function to add a time zone location to a Python datetime object. Then we can use the function astimezone() to convert the existing local time zone into any other time zone we specify (it takes the time zone we want to convert into as an argument).

For example:

<span class="token comment" spellcheck="true"># import timezone from pytz module</span>
<span class="token keyword">from</span> pytz <span class="token keyword">import</span> timezone
<span class="token comment" spellcheck="true"># Create timezone US/Eastern</span>
east <span class="token operator">=</span> timezone<span class="token punctuation">(</span><span class="token string">'US/Eastern'</span><span class="token punctuation">)</span>
<span class="token comment" spellcheck="true"># Localize date</span>
loc_dt <span class="token operator">=</span> east<span class="token punctuation">.</span>localize<span class="token punctuation">(</span>datetime<span class="token punctuation">(</span><span class="token number">2011</span><span class="token punctuation">,</span> <span class="token number">11</span><span class="token punctuation">,</span> <span class="token number">2</span><span class="token punctuation">,</span> <span class="token number">7</span><span class="token punctuation">,</span> <span class="token number">27</span><span class="token punctuation">,</span> <span class="token number">0</span><span class="token punctuation">)</span><span class="token punctuation">)</span>
<span class="token keyword">print</span><span class="token punctuation">(</span>loc_dt<span class="token punctuation">)</span>

<span class="token comment" spellcheck="true"># Convert localized date into Asia/Kolkata timezone</span>
kolkata <span class="token operator">=</span> timezone<span class="token punctuation">(</span><span class="token string">"Asia/Kolkata"</span><span class="token punctuation">)</span>
<span class="token keyword">print</span><span class="token punctuation">(</span>loc_dt<span class="token punctuation">.</span>astimezone<span class="token punctuation">(</span>kolkata<span class="token punctuation">)</span><span class="token punctuation">)</span>

<span class="token comment" spellcheck="true"># Convert localized date into Australia/Sydney timezone</span>
au_tz <span class="token operator">=</span> timezone<span class="token punctuation">(</span><span class="token string">'Australia/Sydney'</span><span class="token punctuation">)</span>
<span class="token keyword">print</span><span class="token punctuation">(</span>loc_dt<span class="token punctuation">.</span>astimezone<span class="token punctuation">(</span>au_tz<span class="token punctuation">)</span><span class="token punctuation">)</span>

2011-11-02 07:27:00-04:00 
2011-11-02 16:57:00+05:30 
2011-11-02 22:27:00+11:00

This module can help make life simpler when working with data sets that include multiple different time zones.

Working with pandas Datetime Objects

Data scientists love pandas for many reasons. One of them is that it contains extensive capabilities and features for working with time series data. Much like datetime itself, pandas has both datetime and timedelta objects for specifying dates and times and durations, respectively.

We can convert date, time, and duration text strings into pandas Datetime objects using these functions:

• to_datetime(): Converts string dates and times into Python datetime objects.
• to_timedelta(): Finds differences in times in terms of days, hours, minutes, and seconds.

And as we’ll see, these functions are actually quite good at converting strings to Python datetime objects by detecting their format automatically, without needing us to define it using strftime patterns.

Let’s look at a quick example:

<span class="token comment" spellcheck="true"># import pandas module as pd</span>
<span class="token keyword">import</span> pandas <span class="token keyword">as</span> pd
<span class="token comment" spellcheck="true"># create date object using to_datetime() function</span>
date <span class="token operator">=</span> pd<span class="token punctuation">.</span>to_datetime<span class="token punctuation">(</span><span class="token string">"8th of sep, 2019"</span><span class="token punctuation">)</span>
<span class="token keyword">print</span><span class="token punctuation">(</span>date<span class="token punctuation">)</span>

2019-09-08 00:00:00

Note that even though we gave it a string with some complicating factors like a “th” and “sep” rather than “Sep.” or “September”, pandas was able to correctly parse the string and return a formatted date.

We can also use pandas (and some of its affiliated numpy functionality) to create date ranges automatically as pandas Series. Below, for example, we create a series of twelve dates starting from the day we defined above. Then we create a different series of dates starting from a predefined date using pd.date_range():

<span class="token comment" spellcheck="true"># Create date series using numpy and to_timedelta() function</span>
date_series <span class="token operator">=</span> date <span class="token operator">+</span> pd<span class="token punctuation">.</span>to_timedelta<span class="token punctuation">(</span>np<span class="token punctuation">.</span>arange<span class="token punctuation">(</span><span class="token number">12</span><span class="token punctuation">)</span><span class="token punctuation">,</span> <span class="token string">'D'</span><span class="token punctuation">)</span>
<span class="token keyword">print</span><span class="token punctuation">(</span>date_series<span class="token punctuation">)</span>

<span class="token comment" spellcheck="true"># Create date series using date_range() function</span>
date_series <span class="token operator">=</span> pd<span class="token punctuation">.</span>date_range<span class="token punctuation">(</span><span class="token string">'08/10/2019'</span><span class="token punctuation">,</span> periods <span class="token operator">=</span> <span class="token number">12</span><span class="token punctuation">,</span> freq <span class="token operator">=</span><span class="token string">'D'</span><span class="token punctuation">)</span>
<span class="token keyword">print</span><span class="token punctuation">(</span>date_series<span class="token punctuation">)</span>

DatetimeIndex(['2019-09-08', '2019-09-09', '2019-09-10', '2019-09-11',
                '2019-09-12', '2019-09-13', '2019-09-14', '2019-09-15',
                '2019-09-16', '2019-09-17', '2019-09-18', '2019-09-19'],
               dtype='datetime64[ns]', freq=None) 
DatetimeIndex(['2019-08-10', '2019-08-11', '2019-08-12', '2019-08-13',
                '2019-08-14', '2019-08-15', '2019-08-16', '2019-08-17',
                '2019-08-18', '2019-08-19', '2019-08-20', '2019-08-21'],
               dtype='datetime64[ns]', freq='D')

Get Year, Month, Day, Hour, Minute in pandas

We can easily get year, month, day, hour, or minute from dates in a column of a pandas dataframe using dt attributes for all columns. For example, we can use df['date'].dt.year to extract only the year from a pandas column that includes the full date.

To explore this, let’s make a quick DataFrame using one of the Series we created above:

<span class="token comment" spellcheck="true"># Create a DataFrame with one column date</span>
df <span class="token operator">=</span> pd<span class="token punctuation">.</span>DataFrame<span class="token punctuation">(</span><span class="token punctuation">)</span>
df<span class="token punctuation">[</span><span class="token string">'date'</span><span class="token punctuation">]</span> <span class="token operator">=</span> date_series df<span class="token punctuation">.</span>head<span class="token punctuation">(</span><span class="token punctuation">)</span>

Now, let’s create separate columns for each element of the date by using the relevant Python datetime (accessed with dt) attributes:

<span class="token comment" spellcheck="true"># Extract year, month, day, hour, and minute. Assign all these date component to new column.</span>
df<span class="token punctuation">[</span><span class="token string">'year'</span><span class="token punctuation">]</span> <span class="token operator">=</span> df<span class="token punctuation">[</span><span class="token string">'date'</span><span class="token punctuation">]</span><span class="token punctuation">.</span>dt<span class="token punctuation">.</span>year
df<span class="token punctuation">[</span><span class="token string">'month'</span><span class="token punctuation">]</span> <span class="token operator">=</span> df<span class="token punctuation">[</span><span class="token string">'date'</span><span class="token punctuation">]</span><span class="token punctuation">.</span>dt<span class="token punctuation">.</span>month
df<span class="token punctuation">[</span><span class="token string">'day'</span><span class="token punctuation">]</span> <span class="token operator">=</span> df<span class="token punctuation">[</span><span class="token string">'date'</span><span class="token punctuation">]</span><span class="token punctuation">.</span>dt<span class="token punctuation">.</span>day
df<span class="token punctuation">[</span><span class="token string">'hour'</span><span class="token punctuation">]</span> <span class="token operator">=</span> df<span class="token punctuation">[</span><span class="token string">'date'</span><span class="token punctuation">]</span><span class="token punctuation">.</span>dt<span class="token punctuation">.</span>hour
df<span class="token punctuation">[</span><span class="token string">'minute'</span><span class="token punctuation">]</span> <span class="token operator">=</span> df<span class="token punctuation">[</span><span class="token string">'date'</span><span class="token punctuation">]</span><span class="token punctuation">.</span>dt<span class="token punctuation">.</span>minute
df<span class="token punctuation">.</span>head<span class="token punctuation">(</span><span class="token punctuation">)</span>

Get Weekday and Day of Year

Pandas is also capable of getting other elements, like the day of the week and the day of the year, from its datetime objects. Again, we can use dt attributes to do this. Note that here, as in Python generally, the week starts on Monday at index 0, so day of the week 5 is Saturday.

<span class="token comment" spellcheck="true"># get Weekday and Day of Year. Assign all these date component to new column.</span>
df<span class="token punctuation">[</span><span class="token string">'weekday'</span><span class="token punctuation">]</span> <span class="token operator">=</span> df<span class="token punctuation">[</span><span class="token string">'date'</span><span class="token punctuation">]</span><span class="token punctuation">.</span>dt<span class="token punctuation">.</span>weekday
df<span class="token punctuation">[</span><span class="token string">'day_name'</span><span class="token punctuation">]</span> <span class="token operator">=</span> df<span class="token punctuation">[</span><span class="token string">'date'</span><span class="token punctuation">]</span><span class="token punctuation">.</span>dt<span class="token punctuation">.</span>weekday_name
df<span class="token punctuation">[</span><span class="token string">'dayofyear'</span><span class="token punctuation">]</span> <span class="token operator">=</span> df<span class="token punctuation">[</span><span class="token string">'date'</span><span class="token punctuation">]</span><span class="token punctuation">.</span>dt<span class="token punctuation">.</span>dayofyear
df<span class="token punctuation">.</span>head<span class="token punctuation">(</span><span class="token punctuation">)</span>

Convert Date Object into DataFrame Index

We can also use pandas to make a datetime column into the index of our DataFrame. This can be very helpful for tasks like exploratory data visualization, because matplotlib will recognize that the DataFrame index is a time series and plot the data accordingly.

To do this, all we have to do is redefine df.index:

<span class="token comment" spellcheck="true"># Assign date column to dataframe index</span>
df<span class="token punctuation">.</span>index <span class="token operator">=</span> df<span class="token punctuation">.</span>date
df<span class="token punctuation">.</span>head<span class="token punctuation">(</span><span class="token punctuation">)</span>

Conclusion

In this tutorial, we’ve taken a deep dive into Python datetime, and also done some work with pandas and the calendar module. We’ve covered a lot, but remember: the best way to learn something is by actually writing code yourself!

If you’d like to practice writing datetime code with interactive answer-checking, check out our Python intermediate course for a lesson on datetime in Python with interactive answer-checking and in-browser code-running.