Skip to content
Related Articles

Related Articles

Table of Contents

Improve Article
Save Article
Like Article

Different ways of sorting Dictionary by Keys and Reverse sorting by keys

  • Difficulty Level : Expert
  • Last Updated : 01 Oct, 2020

Prerequisite: Dictionaries in Python

A dictionary is a collection which is unordered, changeable and indexed. In Python, dictionaries are written with curly brackets, and they have keys and values. We can access the values of the dictionary using keys. In this article, we will discuss 10 different ways of sorting the Python dictionary by keys and also reverse sorting by keys.

Using sorted() and keys():

keys() method returns a view object that displays a list of all the keys in the dictionary. sorted() is used to sort the keys of the dictionary.

Examples:

Input:
my_dict = {'c':3, 'a':1, 'd':4, 'b':2}

Output:
a: 1
b: 2
c: 3
d: 4

Python3




# Initialising a dictionary
my_dict = {'c':3, 'a':1, 'd':4, 'b':2}
  
# Sorting dictionary
sorted_dict = my_dict.keys()
sorted_dict = sorted(sorted_dict)
  
# Printing sorted dictionary
print("Sorted dictionary using sorted() and keys() is : ")
for key in sorted_dict:
    print(key,':', my_dict[key])
Output
Sorted dictionary using sorted() and keys() is : 
a : 1
b : 2
c : 3
d : 4

Using sorted() and items():
items() method is used to return the list with all dictionary keys with values. It returns a view object that displays a list of a given dictionary’s (key, value) tuple pair. sorted() is used to sort the keys of the dictionary.
Examples:
Input:
my_dict = {2:'three', 1:'two', 4:'five', 3:'four'}

Output:
1  'two'
2  'three'
3  'Four'
4  'Five'

Python3



# Initialising dictionary
my_dict = {2: 'three', 1: 'two', 4: 'five', 3: 'four'}
  
# Sorting dictionary
sorted_dict = sorted(my_dict.items())
  
# Printing sorted dictionary
print("Sorted dictionary using sorted() and items() is :")
for k, v in sorted_dict:
    print(k, v)
Output
Sorted dictionary using sorted() and items() is :
1 two
2 three
3 four
4 five

Using sorted() and keys() in single line:
Here, we use both sorted() and keys() in a single line.
Examples:
Input:
my_dict = {'c':3, 'a':1, 'd':4, 'b':2}

Output:
Sorted dictionary is :  ['a','b','c','d']

Python3



# Initialising a dictionary
my_dict = {'c': 3, 'a': 1, 'd': 4, 'b': 2}
# Sorting dictionary
sorted_dict = sorted(my_dict.keys())
  
# Printing sorted dictionary
print("Sorted dictionary is : ", sorted_dict)
Output
Sorted dictionary is :  ['a', 'b', 'c', 'd']

Using sorted() and items() in single line
Here, we use both sorted() and items() in a single line.
Examples:


Input:
my_dict = {'red':'#FF0000', 'green':'#008000', 'black':'#000000', 'white':'#FFFFFF'}

Output:
Sorted dictionary is : 
black  :: #000000
green  :: #008000
red  :: #FF0000
white  :: #FFFFFF

Python3



# Initialising a dictionary
my_dict = {'red': '#FF0000', 'green': '#008000',
           'black': '#000000', 'white': '#FFFFFF'}
  
# Sorting dictionary in one line
sorted_dict = dict(sorted(my_dict .items()))
  
# Printing sorted dictionary
print("Sorted dictionary is : ")
for elem in sorted(sorted_dict.items()):
    print(elem[0], " ::", elem[1])
Output
Sorted dictionary is : 
black  :: #000000
green  :: #008000
red  :: #FF0000
white  :: #FFFFFF

Using a lambda function 
The lambda function returns the key(0th element) for a specific item tuple, When these are passed to the sorted() method, it returns a sorted sequence which is then type-casted into a dictionary.
Examples:
Input:
my_dict = {'a': 23, 'g': 67, 'e': 12, 45: 90}

Output:
Sorted dictionary using lambda is :  {'e': 12, 'a': 23, 'g': 67, 45: 90}


Python3



# Initialising a dictionary
my_dict = {'a': 23, 'g': 67, 'e': 12, 45: 90}
  
# Sorting dictionary using lambda function
sorted_dict = dict(sorted(my_dict.items(), key=lambda x: x[1]))
  
# Printing sorted dictionary
print("Sorted dictionary using lambda is : ", sorted_dict)
Output
Sorted dictionary using lambda is :  {'e': 12, 'a': 23, 'g': 67, 45: 90}

6. Using json :
Python doesn’t allow sorting of a dictionary. But while converting the dictionary to a JSON, you can explicitly sort it so that the resulting JSON is sorted by keys. This is true for the multidimensional dictionary.
Examples:
Input:
my_dict = {"b": 2, "c": 3, "a": 1,"d":4}

Output:
Sorted dictionary is :  {"a": 1, "b": 2, "c": 3,"d":4}

Python3



# Importing json
import json
  
# Initialising a dictionary
my_dict = {"b": 2, "c": 3, "a": 1,"d":4}
  
# Sorting and printind in a single line
print("Sorted dictionary is : ", json.dumps(my_dict, sort_keys=True))
Output
Sorted dictionary is :  {"a": 1, "b": 2, "c": 3, "d": 4}

Using pprint 
The Python pprint module actually already sorts dictionaries by key. The pprint module provides a capability to “pretty-print” arbitrary Python data structures in a form which can be used as input to the interpreter.
Examples:


Input:
my_dict = {1: 2, 3: 4, 4: 3, 2: 1, 0: 0}

Output:
Sorted dictionary is :
{0: 0, 1: 2, 2: 1, 3: 4, 4: 3}

Python3



# Importing pprint
import pprint
  
# Initialising a dictionary
my_dict = {1: 2, 3: 4, 4: 3, 2: 1, 0: 0}
  
# Sorting and printing in a single line
print("Sorted dictionary is :")
pprint.pprint(my_dict)
Using collections and OrderedDict 
The OrderedDict is a standard library class, which is located in the collections module. OrderedDict maintains the orders of keys as inserted.
Examples:
Input:
my_dict = {"b": 2, "c": 3, "a": 1,"d":4}1}

Output:
OrderedDict([('a', 1), ('b', 2), ('c', 3), ('d', 4)])

Python



# Importing OrderedDict
from collections import OrderedDict
  
# Initialising a dictionary
my_dict = {"b": 2, "c": 3, "a": 1,"d":4}
  
# Sorting dictionary
sorted_dict = OrderedDict(sorted(my_dict.items()))
  
# Printing sorted dictionary
print(sorted_dict)
Output
OrderedDict([('a', 1), ('b', 2), ('c', 3), ('d', 4)])

Using sortedcontainers and SortedDict :
Sorted dict is a sorted mutable mapping in which keys are maintained in sorted order. Sorted dict is a sorted mutable mapping. Sorted dict inherits from dict to store items and maintains a sorted list of keys. For this, we need to install sortedcontainers.
sudo pip install sortedcontainers 
Examples:
Input:
my_dict = {"b": 2, "c": 3, "a": 1,"d":4}

Output:
{"a": 1, "b": 2, "c": 3,"d":4}

Python3



# Importing SortedDict
from sortedcontainers import SortedDict
  
# Initialising a dictionary
my_dict = {"b": 2, "c": 3, "a": 1,"d":4}
  
# Sorting dictionary
sorted_dict = SortedDict(my_dict)
  
# Printing sorted dictionary
print(sorted_dict)
Output:
SortedDict({'a': 1, 'b': 2, 'c': 3, 'd': 4})
Using class and function
Examples:
Input:
{"b": 2, "c": 3, "a": 1,"d":4}

Output:
{"a": 1, "b": 2, "c": 3,"d":4}

Python3



class SortedDisplayDict(dict):
    def __str__(self):
        return "{" + ", ".join("%r: %r" % (key, self[key]) for key in sorted(self)) + "}"
  
  
# Initialising dictionary and calling class
my_dict = SortedDisplayDict({"b": 2, "c": 3, "a": 1,"d":4})
  
# Printing dictionary
print(my_dict)
Output
{'a': 1, 'b': 2, 'c': 3, 'd': 4}

Reverse sorting dictionary by keys
Examples:
Input:
my_dict = {"b": 2, "c": 3, "a": 1,"d":4}

Output:
Sorted dictionary is :
['a','b','c','d']
Python3



# Initialising a dictionary
my_dict = {"b": 2, "c": 3, "a": 1,"d":4}
  
# Reverse sorting a dictionary
sorted_dict = sorted(my_dict, reverse=True)
  
# Printing dictionary
print("Sorted dictionary is :")
  
for k in sorted_dict:
  print(k,':',my_dict[k])
Output
Sorted dictionary is :
d : 4
c : 3
b : 2
a : 1


My Personal Notes
arrow_drop_up
Previous
GUI Application for Live Cricket scoreboard Using Python
Next

Python - Solve the Linear Equation of Multiple Variable
Recommended Articles
Page :
Different ways of sorting Dictionary by Values and Reverse sorting by values
05, Nov 20
Python - Append Dictionary Keys and Values ( In order ) in dictionary
30, Jul 20
Python Program to create a sub-dictionary containing all keys from dictionary list
06, Apr 21
Python - Reverse Dictionary Keys Order
28, Apr 20
Python | Ways to change keys in dictionary
26, Feb 19
Different ways to convert a Python dictionary to a NumPy array
29, Aug 20
Reverse string in Python (5 different ways)
21, Oct 17
Python | Ways to split a string in different ways
29, Jul 19
Python | Split dictionary keys and values into separate lists
28, Feb 19
Python program to Swap Keys and Values in Dictionary
08, Dec 18
Python | Test if dictionary contains unique keys and values
28, Apr 19
Python - Sort Dictionary by Values and Keys
27, Jul 20
Python - Common keys in list and dictionary
05, Oct 20
Python program to divide dictionary and its keys into K equal dictionaries
25, Oct 20
Python - Flatten and remove keys from Dictionary
31, Jul 20
Python - Combine two dictionaries having key of the first dictionary and value of the second dictionary
25, Sep 20
Python - Extract selective keys' values Including Nested Keys
27, May 20
Python - Filter immutable rows representing Dictionary Keys from Matrix
29, Oct 20
Python dictionary with keys having multiple inputs
10, Sep 18
Python - Cumulative Mean of Dictionary keys
06, Apr 21
Python Dictionary keys() method
22, Oct 18
Python | Add new keys to a dictionary
21, Nov 18
Python | Remove spaces from dictionary keys
18, Dec 18
Python | Check if given multiple keys exist in a dictionary
25, Dec 18
Article Contributed By :
https://media.geeksforgeeks.org/auth/avatar.png
venniladeenan
@venniladeenan
Vote for difficulty
Current difficulty :
Expert





Article Tags :
Practice Tags :
Report Issue

We use cookies to ensure you have the best browsing experience on our website. By using our site, you
acknowledge that you have read and understood our
Cookie Policy &
        Privacy Policy

Lightbox

Start Your Coding Journey Now!