How to Find Max Value in Dictionary

Problem Formulation and Solution Overview

In this article, you’ll learn how to find the maximum value in a Python dictionary.

To make it more fun, we have the following running scenario:

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You are in the market for a car and have narrowed the search to a few possibilities. Your final choice will be based on the vehicle possessing the maximum MPG. A list of these cars was provided to you in a Dictionary key:value format.

💬 Question: How would we write Python code to determine the maximum value in a Dictionary?

We can accomplish this task by one of the following options:

• Method 1: Use dict.values() and max() to display max value
• Method 2: Use list and max() to display max value
• Method 3: Use dict.keys() and dict.values() to display max value and key.
• Method 4: Use dict.get and max() to display max value and key.

Add the following code to the top of each code snippet. This snippet will allow the code in this article to run error-free.

 import operator

Method 1: Use dict.values() and max() to display max value

Use dict.values() and max() to determine and return the maximum value in a Dictionary using max(dict.values()).

cars_dict = {'Malibu': 18, 'Skylark': 16, 'Satellite': 19, 
            'Torino': 27, 'Challenge': 20}
car_values = cars_dict.values()
max_value = max(car_values)
print(max_value)

This code declares a Dictionary containing five (5) key:value pairs of cars and associated MPG. The values from each pair are extracted and saved to car_values.

The max() function is called and passed car_values to determine and return the maximum value. The result saves to max_value and is output to the terminal.

Output

Method 2: Use list and max() to display max value

Use List and max() to determine and return the maximum value with max(list(cars_dict.values())).

Here’s an example:

cars_dict = {'Malibu': 18, 'Skylark': 16,
             'Satellite': 19, 'Torino': 27, 'Challenge': 20}
max_val = max(list(cars_dict.values()))
print(max_val)  

This code converts a Dictionary into a List, extracting values from the key:value pairs and max() to determine and return the maximum value.
The result saves to max_value and is output to the terminal.

Output

Method 3: Use dict.keys() and dict.values() to display max value and key

This example uses dict.keys() and dict.values() to determine and return the maximum value and associated key.

cars_dict = {'Malibu': 18, 'Skylark': 16,
             'Satellite': 19, 'Torino': 27, 'Challenger': 20}
sort_dict = sorted(cars_dict.items(), key=operator.itemgetter(1), reverse=True)
print(f'{sort_dict[0][0]}:\t{sort_dict[0][1]}')

This code declares a Dictionary containing five (5) key:value pairs of cars and associated MPG.

Then dict.items() and operator.itemgetter() sort the Dictionary key: value pairs in descending order. The maximum key:value pair is set as the first element.

The formatted result is output to the terminal.

Output

Method 4: Use dict.get and max() to display max value and key

Use dict.get and max() to determine and return the maximum value and associated key with max(dict, key=cars_dict.get).

cars_dict = {'Malibu': 18, 'Skylark': 16,
             'Satellite': 19, 'Torino': 27, 'Challenger': 20}
max_val = max(cars_dict, key=cars_dict.get) 
print(max_val, cars_dict[max_val])

This code declares a Dictionary containing five (5) key:value pairs of cars and associated MPG.

Then max is called passing the dictionary and retrieving the key:value pairs, which save to max_val.

The print statement determines the maximum value and outputs the appropriate key:value pair to the terminal.

Output

Summary

These four (4) methods of finding the maximum value in a Dictionary should give you enough information to select the best one for your coding requirements.

Good Luck & Happy Coding!