How to Avoid Global Variables in Python Functions

Описание: Learn how to write clean and efficient Python code by avoiding global variables in functions. Follow our guide to improve your coding skills with a sample number guessing game.
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This video is based on the question https://stackoverflow.com/q/75923592/ asked by the user 'Dan Lewis' ( https://stackoverflow.com/u/12051722/ ) and on the answer https://stackoverflow.com/a/75923647/ provided by the user 'Dominic' ( https://stackoverflow.com/u/19602586/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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How to Avoid Global Variables in Python Functions: A Guide for Beginners

As you delve into Python programming, you might find yourself grappling with the concept of global variables. Coming from a C/Embedded background, many beginners learn to avoid using global variables to maintain clean and manageable code. This article explores a common scenario where using globals can be avoided, demonstrated through a simple number guessing game.

The Problem: Understanding Global Variables

Global variables are defined outside any function and can be accessed anywhere in your code. While they may seem convenient, over-reliance on globals can lead to code that is difficult to read, understand, and maintain. For instance, consider the term num_guesses, which manages the count of attempts made by the player in a game. Using it as a global may not be the best practice.

Here’s a snippet of the problem code used in a simple guess-the-number game:

[[See Video to Reveal this Text or Code Snippet]]

In this case, num_guesses is being referenced in the check_guess function, leading to confusion and dependency on state that's managed outside the function's scope.

The Solution: Refactoring for Best Practices

Step 1: Remove Global Variables

Instead of using global variables, refactor the game to pass necessary values between functions explicitly. For num_guesses, you can rely on maintaining a list of previous guesses within the game logic. Below is an improved version of the code:

Updated Code:

[[See Video to Reveal this Text or Code Snippet]]

Key Changes Explained:

Function Parameters: Functions now receive all necessary data as parameters, allowing for greater readability and reducing dependencies.

Eliminated Globals: The variable num_guesses is removed from check_guess, and instead, we use the guesses list to determine how many guesses were made.

User Experience Improvements: The game now includes more contextual messages and prompts to enhance user interaction.

Conclusion

By eliminating global variables and passing required data between functions, you not only enhance the readability of your code but also embrace the best practices necessary for scalable programming. With a clean structure, maintaining and updating your code in the future will be much more manageable.

Try implementing these concepts in your own Python projects, and you'll find that your understanding and enjoyment of coding will grow significantly!