how to sort dictionary by value python

Sorting a dictionary by its values in Python might sound a bit tricky, but it’s actually pretty straightforward. Imagine you’ve got a box of colored balls, each color representing a different value, and you want to arrange them not by their color but by how many times each color appears.

That’s similar to sorting a dictionary by value. Python makes this easy with some built-in functions that do most of the work for you. This quick guide will show you a simple way to reorder your dictionary, making it organized based on the values instead of the keys. It’s a handy skill for any Python user, helping to make data easier to understand and use.

Understanding Dictionary Structure in Python

In Python, a dictionary is like a storage box where you can keep things and label them so you can find them easily later. Each label (key) is matched with an item (value), allowing you to organize and access your data quickly and efficiently.

# Example of a dictionary
my_dict = {'apple': 5, 'banana': 2, 'orange': 8, 'grape': 3}

Sorting a Dictionary by Value: The Sorted() Function

Here’s how you can sort a dictionary by its values in Python using the sorted() function:

# Sample dictionary
my_dict = {'apple': 5, 'banana': 2, 'orange': 8, 'grape': 1}

# Sorting the dictionary by values using the sorted() function
sorted_dict = {k: v for k, v in sorted(my_dict.items(), key=lambda item: item[1])}

print(sorted_dict)

This will output:

{'grape': 1, 'banana': 2, 'apple': 5, 'orange': 8}

Sorting a Dictionary by Value : Using the Operator Module

Here’s how you can sort a dictionary by its values in Python using the operator module:

import operator

# Sample dictionary
my_dict = {'apple': 5, 'banana': 2, 'orange': 8, 'grape': 1}

# Sorting the dictionary by values using the operator module
sorted_dict = dict(sorted(my_dict.items(), key=operator.itemgetter(1)))

print(sorted_dict)

This will output:

{'grape': 1, 'banana': 2, 'apple': 5, 'orange': 8}

To sort the dictionary in descending order, you can modify the key parameter and use it with the sorted() function like this:

# Sorting the dictionary by values in descending order using the operator module
sorted_dict_desc = dict(sorted(my_dict.items(), key=operator.itemgetter(1), reverse=True))

print(sorted_dict_desc)

This will output:

{'orange': 8, 'apple': 5, 'banana': 2, 'grape': 1}

In both cases, the operator.itemgetter(1) function extracts the value from each dictionary item, which is then used as the key for sorting. You can use this approach to sort the dictionary based on its values either in ascending or descending order.

Practical Examples

Sorting dictionaries by values is a common task in various practical scenarios. Here are practical examples and use cases:

# Dictionary representing student scores
student_scores = {
    'Alice': 85,
    'Bob': 72,
    'Charlie': 90,
    'David': 68,
    'Eva': 95
}

# Sorting the dictionary by scores in descending order
sorted_scores = dict(sorted(student_scores.items(), key=lambda item: item[1], reverse=True))

# Displaying the sorted scores
for student, score in sorted_scores.items():
    print(f"{student}: {score}")

In this example, we have a dictionary student_scores where the keys are the names of students and the values are their respective scores. We want to sort this dictionary by scores in descending order to determine the ranking of students based on their scores.

We use the sorted() function along with a lambda function as the key to sort the dictionary by values (scores) in descending order. Then, we convert the sorted list of tuples back into a dictionary.

Finally, we iterate over the sorted dictionary and print each student’s name along with their corresponding score. This will display the students’ scores in descending order, effectively providing a ranking based on their performance.

Eva: 95
Charlie: 90
Alice: 85
Bob: 72
David: 68

Questions You Might Have