Python: how to sort array of dicts by two fields?

Question

I am somewhat new to Python...

I have an array of dicts that I got by reading a file containing JSON messages, i.e. using something like this:

import json
ws = []
with open('messages.txt', 'r') as f:
    for line in f:
        data = json.loads(line)
        ws.append(data)

Each JSON message has, among other things, three fields: "date" and "type" and "location". I need to sort the array first by date, then by type within each block of identical dates, then by location within each block of identical types. How can I do that? Thx much!

Answer 1

ws.sort(key=lambda datum: (datum['date'], datum['type'], datum['location']))

Tuples are sorted naturally first by first element, then by succeeding elements.