The core methods of Python's processing of dates and times include parsing and formatting, calculating time differences and processing time zones. 1. Use datetime.strptime() to parse the string into a datetime object, and use strftime() to convert the string back to the string in format code such as %Y%m%d; 2. Calculate the time difference between the two datetime objects through timedelta, supports accessing attributes such as .days.seconds, and can also add and subtract time units such as timedelta(days=7); 3. The default datetime has no time zone information, and you can use the built-in zoneinfo module in Python 3.9 to add time zones such as .replace(tzinfo=ZoneInfo("America/New_York")). It is recommended to convert cross-region events to UTC time first to avoid daylight saving time problems.
Working with dates and times in Python is pretty straightforward thanks to built-in modules like datetime
and time
. If you've ever struggled with date formatting, time zones, or calculating durations, Python has tools that make handling these tasks easier than you might think.

Parsing and Formatting Dates
One of the most common tasks is converting between strings and datetime
objects. For example, if you get a date from a file or user input like "2024-03-15"
, you'll want to parse it into something you can work with.
You can use datetime.strptime()
for parsing and strftime()
for formatting:

from datetime import datetime # Parsing a string into a datetime object date_str = "2024-03-15" date_obj = datetime.strptime(date_str, "%Y-%m-%d") # Formatting back to a string formatted = date_obj.strftime("%B %d, %Y") print(formatted) # March 15, 2024
The format codes like %Y
(year), %m
(month), and %d
(day) are key here — and they're easy to mix and match depending on your input format.
Some common ones:

-
%H
: hour (00–23) -
%M
: minute (00–59) -
%S
: second (00–59) -
%A
: full weekday name -
%a
: abbreviated weekday name
Calculating Time Differences
If you need to calculate how much time is between two moments — say, how many days until an event — timedelta
is your friend. It represents a duration, not a specific point in time.
Here's how you can calculate the number of days between two dates:
from datetime import datetime start = datetime(2024, 3, 10) end = datetime(2024, 3, 15) diff = end - start print(diff.days) # Output: 5
This subtraction gives you a timedelta
object, and you can access .days
, .seconds
, or even total seconds via .total_seconds()
.
It's also useful for adding or subtracting time:
- Add 7 days to a date:
some_date timedelta(days=7)
- Subtract 3 hours:
some_datetime - timedelta(hours=3)
Handling Time Zones
By default, Python's datetime
doesn't include time zone information — but you can add it using libraries like pytz
or Python 3.9 's built-in zoneinfo
.
Using zoneinfo
(no extra install needed in Python 3.9):
from datetime import datetime from zoneinfo import ZoneInfo naive = datetime(2024, 3, 15, 12, 0) # No timezone info aware = naive.replace(tzinfo=ZoneInfo("America/New_York")) print(aware)
Time zones matter when dealing with events across regions — especially when converting between local and UTC time. UTC is often used as a baseline because it avoids daylight saving issues.
If you're storing timestamps in a database or sending data across systems, always consider normalizing to UTC first.
That's the core of working with dates and times in Python. These tools cover most everyday needs — parsing, formatting, calculating differences, and managing time zones. There are more advanced options like pandas
or third-party libraries such as arrow
or pendulum
, but for many projects, the standard library is enough.
Basically that's it.
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