Sort a Dictionary in Python by Keys

Python allows dictionaries to be sorted using the built-in sorted() function. Although dictionaries in Python 3.7+ preserve insertion order, we can still create a new dictionary sorted by its keys using various methods.

In this article, we will explore different ways to sort a dictionary in Python by its keys.

Using sorted() with a for Loop

We can use the sorted() function on the dictionary keys and then iterate through them to build a new dictionary in key order.

Example

Following is an example, which shows how to sort a dictionary in Python using the sorted() function -

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

# Creating a new dictionary by sorting keys
sorted_dict = {}
for key in sorted(dictionary.keys()):
   sorted_dict[key] = dictionary[key]

print(sorted_dict)

Following is the output of the above program -

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

Using Dictionary Comprehension

Python provides a concise way to sort dictionaries using dictionary comprehension. The keys are sorted and values are assigned in a single line.

Example

Here is an example that uses dictionary comprehension to sort the dictionary using Python -

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

# Sorting dictionary by keys using comprehension
sorted_dict = {key: dictionary[key] for key in sorted(dictionary)}

print(sorted_dict)

Below is the output of the above program -

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

Using collections.OrderedDict

The OrderedDict() function from the collections module remembers the order in which keys are inserted. It is useful when order is important.

Example

Following is an example in which we use the OrderedDict()function of the collections module to sort the dictionary keys -

from collections import OrderedDict

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

# Sorting dictionary by keys using OrderedDict
sorted_dict = OrderedDict(sorted(dictionary.items()))

print(sorted_dict)

Here is the output of the above program -

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