Pattern Generator - Learn String Rules from Examples
Provide match and non-match string examples; a decision tree learns the pattern and exports it as Rust, JavaScript, or regex.
How to use
- 1
Add match examples
Enter strings that should match (e.g. valid emails, IDs, codes).
- 2
Add non-match examples
Enter strings that should NOT match.
- 3
Train and export
Click Train to fit the decision tree, then export as Rust, JavaScript, or a best-effort regex.
Why use this tool?
- Learns structural patterns without writing regex by hand
- Exports clean Rust or JavaScript validation functions
- Trains a CART decision tree on 15 string features in milliseconds
Frequently asked questions
- How many examples do I need?
- At least 4 match and 4 non-match examples. More examples improve accuracy.
- How accurate is the regex export?
- The regex is a best-effort approximation. The Rust and JS exports are exact and recommended for production use.
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