Sort Python list of objects by date

Question:

I have a Python list called results. Each result in the results list has a person object, and each person object has a birthdate (result.person.birthdate). The birthdate is a datetime object.

I would like to order the list by birthdate with the oldest first. What is the most Pythonic way to do this?

Asked By: shane

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Answers:

results.sort(key=lambda r: r.person.birthdate)
Answered By: Amber

Totally agree with Amber, but there is another way of sorting by attribute (from the wiki: https://wiki.python.org/moin/HowTo/Sorting):

from operator import attrgetter
sorted_list = sorted(results, key=attrgetter('person.birthdate'))

This method can actually be even faster than sorting with lambda

Answered By: yentsun
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