RegEx Generator

CategoryCoding
Authorersinyilmaz
LicenseMIT
Rating4.40/5
Uses10.9K

What it does

Stop wasting time manually testing character classes and quantifiers. This tool generates precise Regular Expression patterns based on your specific data matching requirements. It is particularly useful when you need a quick, copy-pasteable string for validation logic, log parsing, or text scraping without wading through long-winded AI explanations. By stripping away the conversational filler, you get a clean output that integrates directly into your IDE or configuration files, speeding up your development workflow and reducing the cognitive load of writing complex patterns from scratch.

Use cases

  • Input Validation: Quickly generating a pattern to validate user-submitted email addresses or phone numbers in a registration form.
  • Log Analysis: Creating a regex to extract specific timestamp formats or error codes from massive server log files.
  • Web Scraping: Identifying specific URL structures or HTML attributes within a raw page source.
  • Data Cleaning: Finding and replacing inconsistent date formats across a legacy CSV dataset.

How to use

Define the specific pattern you need (e.g., "IPv4 address", "ISO 8601 date", or "US Zip Code") and pass it to the AI. For the most consistent results, use the following system prompt:
markdown
Act as a Regular Expression (RegEx) Generator. Your role is to generate regular expressions that match specific patterns in text. You should provide the regular expressions in a format that can be easily copied and pasted into a regex-enabled text editor or programming language.

Your task is to:
  • Generate regex patterns based on the user's specified need, such as matching an email address, phone number, or URL.

  • Provide only the regex pattern without any explanations or examples.


Rules:
  • Focus solely on the accuracy of the regex pattern.

  • Do not include explanations or examples of how the regex works.


Variables:
  • ${pattern:email} - Specify the type of pattern to match (e.g., email, phone, URL).

Tips

  • Specify the Flavor: Since regex syntax varies between languages, mention if you need the pattern for a specific engine (e.g., "PCRE", "JavaScript", or "Python").
  • Define Constraints: Instead of just saying "phone number," specify the format (e.g., "US phone number with optional area code in parentheses") to get a more accurate match.
  • Provide Edge Cases: If you know your data contains specific anomalies, mention them in your request to ensure the regex handles those cases correctly.
  • Request Anchors: If you need the pattern to match the entire string rather than a substring, explicitly ask for start (^) and end ($) anchors.

Notes

  • Verification Required: Always test the generated regex against a tool like RegEx101 to ensure it behaves as expected before deploying it to production.
  • Complexity Trade-offs: Highly restrictive patterns can sometimes lead to "catastrophic backtracking" on very large strings; keep an eye on performance for complex patterns.
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