EmbeddingGemma 2: an open, lightweight multimodal embedding model
deepmind.google·6d ago
AI Engineering
Lobsters·29d ago·5 min read
Can a regex match valid card numbers?
TL;DR
Validating credit card numbers using regex and the Luhn algorithm is a complex challenge. The article explores the intricacies of this task and provides insights into potential solutions.
✦ Why It Matters
Consider reviewing your payment validation methods to ensure compliance with credit card standards.
Key Takeaways
- Understand the structure of credit card numbers and the Luhn algorithm.
- Explore the use of DFAs for validating complex patterns.
- Be aware of the limitations of regex for specific validation tasks.
- Consider the computational cost of generating large regex expressions.
How It Works
The DFA tracks the parity of the string length and computes a running sum modulo 10 as it processes each digit. This allows it to validate the Luhn check digit efficiently.