Using Pyodide and WebAssembly: A Beginner’s Guide

Have you ever wanted to run Python code directly in your web browser? With the power of Pyodide and WebAssembly, you can do just that! This tutorial will guide you through the process of setting up Pyodide and using it to execute Python code in a web environment.

Prerequisites

Before we dive into the tutorial, make sure you have the following:

A basic understanding of HTML and JavaScript.
A modern web browser (like Chrome, Firefox, or Edge).
Access to a code editor (like Visual Studio Code or any text editor of your choice).

Step-by-Step Guide

Step 1: Setting Up Your HTML File

First, create a new HTML file. You can name it index.html. This file will serve as the foundation for our project.

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Pyodide Example</title>
</head>
<body>
    <h1>Running Python in the Browser with Pyodide</h1>
    <script src="https://cdn.pyodide.org/latest/full/pyodide.js"></script>
    <script>
        // Your Python code will go here
    </script>
</body>
</html>

Step 2: Loading Pyodide

Next, we need to load Pyodide in our HTML file. This is done by including the Pyodide script in the <head> section of your HTML file. The script source is:

https://cdn.pyodide.org/latest/full/pyodide.js

This line of code will load the Pyodide library, allowing us to run Python code in the browser.

Step 3: Writing Python Code

Now, let’s write some Python code that we want to execute. Inside the <script> tag, add the following code:

async function main() {
    let pyodide = await loadPyodide();
    await pyodide.runPythonAsync(`
        import sys
        sys.version
    `);
}
main();

This code defines an asynchronous function called main that loads Pyodide and runs a simple Python command to get the Python version.

Step 4: Running Your Code

To see your code in action, open your index.html file in a web browser. You should see the output of your Python code in the console. To view the console, right-click on the page, select Inspect, and navigate to the Console tab.

Explanation of Key Concepts

Let’s break down some of the key concepts we used in this tutorial:

Pyodide: A Python interpreter that runs in the browser, allowing you to execute Python code without needing a server.
WebAssembly: A binary instruction format that enables high-performance applications on web pages. Pyodide uses WebAssembly to run Python code efficiently.
Asynchronous Functions: Functions that allow you to perform tasks without blocking the main thread, making your web applications more responsive.

Conclusion

Congratulations! You have successfully set up Pyodide and run Python code in your web browser. This opens up exciting possibilities for web development, allowing you to leverage Python’s capabilities directly in the frontend. Explore further by trying out different Python libraries and functionalities within Pyodide.

For more information, check out the original post Running Python Programs in Your Browser”>here. You can also find additional resources and documentation Towards Data Science”>here.

Source: Original Article