How do I group a list of row objects by year in python?

Question

I have a class for example:

class Row(object):
    def __init__(self, res_json):
        test = res_json['test']
        value = res_json['value']
        year = res_json['date'][0:4]

If I have a list of row objects and want to group them by year what's the best way to do this?

Possible duplicate of [Parsing a json and grouping contents](https://stackoverflow.com/questions/32497253/parsing-a-json-and-grouping-contents) — Stevy, Apr 01 '19 at 14:21
Yes, I'm actually trying to avoid pandas due to schema issues with our system — staten12, Apr 01 '19 at 14:21

score 2 · Accepted Answer · answered Apr 01 '19 at 14:27

2

Use itertools.groupby:

from itertools import groupby
from operator import attrgetter

rows = []  # list of row objects

for year, group in groupby(rows, key=attrgetter('year')):
    # do stuff with the year and the group here

answered Apr 01 '19 at 14:27

gmds

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How do I group a list of row objects by year in python?

1 Answers1