How to Create QR Codes in Python: A Beginner's Guide

QR codes, short for Quick Response codes, offer a fast way to access information by simply scanning a patterned grid of black and white squares. These versatile codes are widely used today, from restaurants displaying digital menus to shops facilitating contactless payments. Event organizers also use them for efficient check-ins. In this guide, we'll explore how to generate these useful codes using Python's QR code generator.

Getting Started with QR Codes

QR codes store data in binary form via a grid pattern. You can customize these codes with different colors, backgrounds, and frames while keeping the foundational pattern intact. For this tutorial, we'll focus on creating QR codes using Python's "qrcode" package.

Installing the QR Code Package

Before we dive into creating QR codes, we need to install the necessary Python package. Using your preferred IDE, such as PyCharm, open the terminal and execute the following command:

pip install qrcode[pil]

This command installs the "qrcode" package along with the Pillow library for additional image processing capabilities, enabling us to save QR codes as PNG files.

Generating a Basic QR Code

Once the package is installed, you can start generating QR codes. Begin by importing the library and creating a simple QR code with the following code:

import qrcode

img = qrcode.make("Your URL or data here")
img.save("simple_qr.png")

This code snippet generates a basic QR code and saves it as a PNG file. But there's more you can do if you're interested in customizing and experimenting further.

Exploring Advanced QR Code Options

For advanced customization, we'll delve into various attributes of the "qrcode" package.

Creating a QR Code Object

The first step in advanced QR code generation is to create a QR code object:

qr = qrcode.QRCode()

This object acts as a container for various attributes and methods, allowing for more detailed customization.

Setting the Version

The version of a QR code determines its size. You can choose a version from 1 to 40, with the smallest being a 21x21 grid. Here's how you can set the version:

qr = qrcode.QRCode(version=5)

Changing the version alters the grid size, with higher versions supporting more data.

Error Correction Levels

Error correction ensures that a QR code remains scannable even if partially damaged. You can choose from four levels:

• L: 7% error correction
• M: 15% error correction
• Q: 25% error correction
• H: 30% error correction

Set the error correction level as follows:

qr = qrcode.QRCode(error_correction=qrcode.constants.ERROR_CORRECT_H)

Higher error correction levels increase the resilience of the QR code but also enlarge its size.

Box Size and Border

The box size refers to the number of pixels each box in the QR code grid uses. Meanwhile, the border defines the space around the QR code. Here's how to set these attributes:

qr = qrcode.QRCode(box_size=10, border=4)

Adjusting these values changes the visual appearance and dimensions of the QR code.

Adding Data to the QR Code

Once your QR code object is set up, you can add data using the add_data method. This can be a URL, text, or any string:

qr.add_data("https://example.com")

After adding data, use the make method to finalize the QR code:

qr.make(fit=True)

This automatically adjusts the QR code size to fit the input data optimally.

Generating and Saving the Image

With the QR code object ready, create and save the image using the following code:

img = qr.make_image(fill_color="pink", back_color="black")
img.save("custom_qr.png")

This example generates a QR code with a pink foreground and black background, demonstrating the customization potential available with the library.

Conclusion

This tutorial introduced you to creating QR codes using Python's qrcode package. We've covered basic generation, as well as advanced customization options using classes and objects. With these tools, you can create QR codes tailored to your specific needs. As you gain more experience, feel free to explore further customization and integration possibilities.