Sort a dictionary by its values' values

Question

I currently have some JSON that looks like this:

{
    "Chile": {
        "num_of_unique_ips": 1,
        "num_of_unique_asns": 1,
        "asns": {
            "AS16629 CTC. CORP S.A. (TELEFONICA EMPRESAS)": 1
        }
    },
    "China": {
        "num_of_unique_ips": 1,
        "num_of_unique_asns": 1,
        "asns": {
            "AS4808 China Unicom Beijing Province Network": 1
        }
    }, # this goes on and on for ever country
}

I converted it to a dictionary by running:

import json
login_by_country = json.loads(open('login_by_country.json', 'r'))

How would i go about sorting this dictionary by each country's num_of_unique_ips value?

Answer 1

sorted(login_by_country.items(), key=lambda it: it[1]['num_of_unique_ips'])

This will return a list of (country, values_dict) pairs. You can convert it back to a dictionary while keeping the sorted order by passing it to OrderedDict , or the regular dict if you're using a version of Python which guarantees dict ordering (cpython 3.6+ or pypy 2.5).

Answer 2

As @johrsharpe said in comment - dictionary doesn't have to keep order (but probably they will keep in in newest Python).

You can create list with pairs (num_of_unique_ips , country) and then you can easily sort it and keep in order.

logins_by_country = {
    "Chile": {
        "num_of_unique_ips": 1,
        "num_of_unique_asns": 1,
        "asns": {
            "AS16629 CTC. CORP S.A. (TELEFONICA EMPRESAS)": 1
        }
    },
    "China": {
        "num_of_unique_ips": 1,
        "num_of_unique_asns": 1,
        "asns": {
            "AS4808 China Unicom Beijing Province Network": 1
        }
    }, # thi
}

data = [(val["num_of_unique_ips"], key) for key, val in logins_by_country.items()]

order = sorted(data) 

print(order)

Result. It sorts by num_of_unique_ips and country (if they have the sam num_of_unique_ips )

[(1, 'Chile'), (1, 'China')]

and now you can use it to get data from dictionary in expected order.

for number, country in order:
    print(logins_by_country[country])

You can also use it to create OrderedDict which will keep order

from collections import OrderedDict

new_dict = OrderedDict()

for number, country in order:
    new_dict[country] = logins_by_country[country]

print(new_dict)