Sorting list by date Python

Question

My data is in the form: [{'value': 2, 'year': u'2015'}, {'value': 4, 'year': u'2016'}, {'value': 3, 'year': u'2018'}, {'value': 0, 'year': u'2014'}, {'value': 0, 'year': u'2017'}]

I want to sort it by year. Can you please help?

Maybe the data structure you are using (list of dictionaries) is not adapted to whatever you want to achieve). — Tarik, Aug 05 '18 at 17:33
@Tarik, I don't think so, it is really doable. See my answer about `itemgetter` — wowkin2, Aug 05 '18 at 17:34

score 2 · Answer 1 · answered Aug 05 '18 at 17:30

2

You need to specify the key function applied for comparing when sorting:

my_data = sorted( my_data, key = lambda x : x["year"])

answered Aug 05 '18 at 17:30

Learning is a mess

5,905
5
30
64

The string comparison will break if you have a year like `987`. You might want to use: `lambda x: int(x['year'])` – Matthias Aug 05 '18 at 17:34
True, my code was specific to this data. – Learning is a mess Aug 05 '18 at 17:35

score 0 · Answer 2 · answered Aug 05 '18 at 17:33

You should use itemgetter for that:

>>> from operator import itemgetter
>>> data = [{'value': 2, 'year': u'2015'}, {'value': 4, 'year': u'2016'}, {'value': 3, 'year': u'2018'}, {'value': 0, 'year': u'2014'}, {'value': 0, 'year': u'2017'}]
>>> result = sorted(data, key=itemgetter('year'))
>>> print(result)
[{'value': 0, 'year': '2014'}, {'value': 2, 'year': '2015'}, {'value': 4, 'year': '2016'}, {'value': 0, 'year': '2017'}, {'value': 3, 'year': '2018'}]

Sorting list by date Python

2 Answers2