Parsing ISO 8601 timestamps in plain Django

By Dan Bader — Get free updates of new posts here.

“How do I parse an ISO 8601 formatted date in Django without bringing in extra dependencies?”

If you do any web development with Python and Django then you’ll inevitable find yourself wanting to parse ISO 8601 timestamps into Python’s native datetime.datetime objects at some point. In other words, given a timestamp string like '2016-12-11T09:27:24.895' we want to convert it into a proper Python datetime object for further processing.

If you search Google on how to do this you’ll often find people recommend the 3rd party python-dateutil module. Python-dateutil is a great choice – but in some cases it does more than you really need.

If you’re already using Django you can parse ISO 8601 timestamps without bringing in another dependency using django.utils.dateparse.parse_datetime.

Here’s how:

from django.utils.dateparse import parse_datetime
parsed = parse_datetime('2001-12-11T09:27:24.895551')
assert parsed == datetime(2001, 12, 11, 9, 27, 20, 608645)

Note that if you pass a malformed value to parse_datetime it can throw a KeyError, ValueError, or TypeError exception so you might want to be ready to handle those.

Importantly, parse_datetime also understands timezone-aware timestamps and correctly sets the UTC offset on the resulting datetime object:

from django.utils.dateparse import parse_datetime
from django.utils.timezone import is_aware, utc

expected = datetime.datetime(2016, 4, 27, 11, 18, 42, 303886, tzinfo=utc)
parsed = parse_datetime('2016-04-27T11:18:42.303886+00:00')

assert parsed == expected
assert is_aware(parsed)

<strong><em>Improve Your Python</em></strong> with a fresh 🐍 <strong>Python Trick</strong> 💌 every couple of days

Improve Your Python with a fresh 🐍 Python Trick 💌 every couple of days

🔒 No spam ever. Unsubscribe any time.

This article was filed under: django, python, and web-development.

Related Articles:

How to stop Django Rest Framework from leaking docstrings into OPTIONS responses – When you make an HTTP OPTIONS request against an endpoint in a Django Rest Framework app you might be surprised about what you’ll find in the response to that request.
Debugging memory usage in a live Python web app – I worked on a Python web app a while ago that was struggling with using too much memory in production. A helpful technique for debugging this issue was adding a simple API endpoint that exposed memory stats while the app was running.
Sublime Text plugin review: Djaneiro – A review of Djaneiro, a Sublime Text plugin for Django development.
Functional linked lists in Python – Linked lists are fundamental data structures that every programmer should know. This article explains how to implement a simple linked list data type in Python using a functional programming style.
OS X notifications for your pytest runs – This article shows you how to use the pytest-osxnotify, a plugin for pytest that adds native Mac OS X notifications to the pytest terminal runner.

Latest Articles:

Interfacing Python and C: The CFFI Module – How to use Python’s built-in CFFI module for interfacing Python with native libraries as an alternative to the “ctypes” approach.
Write More Pythonic Code by Applying the Things You Already Know – There’s a mistake I frequently make when I learn new things about Python… Here’s how you can avoid this pitfall and learn something about Python’s “enumerate()” function at the same time.
Working With File I/O in Python – Learn the basics of working with files in Python. How to read from files, how to write data to them, what file seeks are, and why files should be closed.
How to Reverse a String in Python – An overview of the three main ways to reverse a Python string: “slicing”, reverse iteration, and the classic in-place reversal algorithm. Also includes performance benchmarks.
Mastering Click: Writing Advanced Python Command-Line Apps – How to improve your existing Click Python CLIs with advanced features like sub-commands, user input, parameter types, contexts, and more.
Working with Random Numbers in Python – An overview for working with randomness in Python, using only functionality built into the standard library and CPython itself.

← Browse All Articles

🐍 Python Tricks 💌