How to sort a dictionary in Python

Sorting By Keys and Values

Python offers the built-in keys functions keys() and values() functions to sort the dictionary. It takes any iterable as an argument and returns the sorted list of keys. We can use the keys to sort the dictionary in the ascending order. 

Example -

names = {1:'Alice' ,2:'John' ,4:'Peter' ,3:'Andrew' ,6:'Ruffalo' ,5:'Chris' }  
#print a sorted list of the keys  
print(sorted(names.keys()))  
#print the sorted list with items.  
print(sorted(names.items()))  

Output:

[1, 2, 3, 4, 5, 6]
[(1, 'Alice'), (2, 'John'), (3, 'Andrew'), (4, 'Peter'), (5, 'Chris'), (6, 'Ruffalo')]

Explanation -

In the above code, we have declared a dictionary names. We used the built-in function along with the sorted() function that returned the list of the sorted keys. Next, we used the items() function to get the dictionary in the sorted order.

Sorting Algorithm

There are various sorting algorithm to sort a dictionary; we can use other arguments in the sorted method. Let's understand the following example.

Example -

daynames = { 'one' : 'Monday' ,  'six' : 'Saturday' ,'three' : 'Wednesday' ,  'two' : 'Tuesday' , 'five': 'Friday' ,  'seven': 'Sunday' }  
print(daynames)  
number = { 'one' : 1 , 'two' : 2 , 'three' : 3 , 'four' : 4 , 'five' : 5 , 'six' : 6 , 'seven' : 7}  
print(sorted(daynames , key=number.__getitem__))  
print([daynames[i] for i in sorted(daynames , key=number.__getitem__)])  

Output:

{'one': 'Monday', 'six': 'Saturday', 'three': 'Wednesday', 'two': 'Tuesday', 'five': 'Friday', 'seven': 'Sunday'}
['one', 'two', 'three', 'five', 'six', 'seven']
['Monday', 'Tuesday', 'Wednesday', 'Friday', 'Saturday', 'Sunday']

Reverse the sorted Order

The dictionary can be reversed using the reverse argument. Let's understand the following example.

Example -

a = {'a':2 ,'b':1 ,'c':3 ,'d':4 ,'e':5 ,'f':6 }  
print(sorted(a.values() ,  reverse= True)) 

Output:

[6, 5, 4, 3, 2, 1]

In this tutorial, we have discussed how to sort the dictionary in Python. A sorted dictionary is easy to handle the large amount of data and gives us a fast search result.