Sort a Nested Dictionary by Value in Python

Below are some of the ways by which we can sort a nested dictionary by value in Python:

Using sorted() Method
Using itemgetter() Method
Using json.dumps() Method
Using Recursion

Sort a Nested Dictionary Using sorted() with a Custom Sort Key

In this example, a nested dictionary `nested_dict` with keys ‘a’, ‘b’, and ‘c’ is sorted based on the value associated with the ‘key’ key within each nested dictionary using sorted() method. The result is a new dictionary `sorted_dict` with keys ordered by ascending values of the ‘key’ in the nested dictionaries.

Python3

nested_dict = {'a': {'key': 3}, 'b': {'key': 1}, 'c': {'key': 2}}
 
sorted_dict = dict(
    sorted(nested_dict.items(), key=lambda item: item[1]['key']))
 
print(sorted_dict)

Output

{'b': {'key': 1}, 'c': {'key': 2}, 'a': {'key': 3}}

Sort a Nested Dictionary by Value Using itemgetter() Method

In this example, a nested dictionary `nested_dict` with keys ‘a’, ‘b’, and ‘c’ is sorted based on the values associated with the ‘key’ key within each nested dictionary, using the itemgetter() function. The result is a new dictionary `sorted_dict` with keys ordered by ascending values of the ‘key’ in the nested dictionaries.

Python3

from operator import itemgetter
 
nested_dict = {'a': {'key': 3}, 'b': {'key': 1}, 'c': {'key': 2}}
 
sorted_dict = dict(
    sorted(nested_dict.items(), key=lambda item: itemgetter('key')(item[1])))
 
print(sorted_dict)

Output

{'b': {'key': 1}, 'c': {'key': 2}, 'a': {'key': 3}}

Sort a Nested Dictionary by Value Using json.dumps() Method

In this example, the nested dictionary `nested_dict` is sorted based on keys in ascending order using the json.dumps() and `json.loads` functions. Note that sorting is applied to the keys, not the values within the nested dictionaries.

Python3

import json
 
nested_dict = {3: {'key': 3}, 1: {'key': 1}, 2: {'key': 2}}
 
sorted_dict = json.loads(json.dumps(nested_dict, sort_keys=True))
print(sorted_dict)

Output

{'1': {'key': 1}, '2': {'key': 2}, '3': {'key': 3}}

Sort a Nested Dictionary by Value Using Recursion

In this example, the function `sort_nested_dict` recursively sorts a nested dictionary `d` based on both keys and values. It iterates through the items of the dictionary, checking if a value is itself a dictionary. If it is, the function is called recursively to sort the inner dictionary. The result, stored in `sorted_dict`, is a dictionary with keys ordered alphabetically and values sorted recursively if they are dictionaries.

Python3

def sort_nested_dict(d):
    for key, value in d.items():
        if isinstance(value, dict):
            d[key] = sort_nested_dict(value)
    return dict(sorted(d.items(), key=lambda item: str(item[1]) if not isinstance(item[1], dict) else str(sort_nested_dict(item[1]))))
 
nested_dict = {'a': {'key': 3}, 'b': {'key': 1},
               'c': {'key': 2, 'inner': {'z': 3, 'x': 1}}}
 
sorted_dict = sort_nested_dict(nested_dict)
print(sorted_dict)

Output

{'b': {'key': 1}, 'c': {'key': 2, 'inner': {'x': 1, 'z': 3}}, 'a': {'key': 3}}