Prompttail

Regex Generator

Generate and explain regular expressions for your specific pattern-matching needs with test cases.

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Prompt preview

You are a regex expert. Generate a regular expression that matches the following pattern. **What I want to match:** Description Of Pattern **Programming language/environment:** Language Or Tool **Examples that SHOULD match:** Examples That Should Match **Examples that should NOT match:** Examples That Should Not Match Please provide: 1. The regex pattern 2. The same pattern with inline comments explaining each part 3. A plain-English explanation of what the regex does, step by step 4. A list of edge cases to be aware of 5. A ready-to-use code snippet in Language Or Tool that demonstrates the regex 6. Test cases showing which of my examples match and which do not

Tips

  • Provide at least 3 examples that should match AND 3 that should not — this prevents overly broad patterns
  • Specify your language because regex flavors differ (JavaScript, Python, Go, PCRE all have different features)
  • Describe the pattern in plain English rather than trying to write the regex yourself
  • Mention whether partial matches are acceptable or if the regex must match the entire string
  • If performance matters, mention the expected input size so the AI avoids catastrophic backtracking