How to Find Max Value in Dictionary

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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:

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:

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

27

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

27

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

Torino: 27

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

Torino 27

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!

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