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💻DeveloppementIntermediateAll AIs

Generate Precise Regular Expressions with AI

This prompt generates precise and documented regular expressions, tailored to your programming language, with detailed explanations and built-in tests.

Paste in your AI

Paste this prompt in ChatGPT, Claude or Gemini and customize the variables in brackets.

Tu es un expert en expressions régulières (regex). Je travaille avec le langage [LANGAGE_DE_PROGRAMMATION] et j'ai besoin d'une regex pour le cas suivant :

**Objectif** : [DESCRIPTION_DU_PATTERN_A_CAPTURER]

**Exemples de chaînes qui doivent matcher** :
- [EXEMPLE_VALIDE_1]
- [EXEMPLE_VALIDE_2]

**Exemples de chaînes qui ne doivent PAS matcher** :
- [EXEMPLE_INVALIDE_1]
- [EXEMPLE_INVALIDE_2]

Pour chaque regex que tu proposes, fournis :
1. La regex complète prête à l'emploi dans [LANGAGE_DE_PROGRAMMATION]
2. Une explication segment par segment de chaque partie de la regex
3. Un tableau de tests montrant le résultat (match/no match) pour chaque exemple
4. Les cas limites potentiels auxquels faire attention
5. Une version simplifiée si la regex est complexe, en expliquant les compromis
6. Un snippet de code fonctionnel dans [LANGAGE_DE_PROGRAMMATION] utilisant cette regex pour valider ou extraire les données

Why this prompt works

<p>This prompt is designed to produce reliable and understandable regular expressions. By providing both valid and invalid examples, you guide the AI toward a regex that captures exactly what you need, without false positives or false negatives.</p><p>The key to a good result lies in the <strong>precision of your description</strong>. The more varied and representative your examples, the more robust the regex will be. Do not hesitate to include edge cases in your examples: empty strings, special characters, unusual formats.</p><p><strong>Advanced tip</strong>: if your need is complex, first ask for a simple version covering 90% of cases, then refine progressively. Also specify whether performance matters (some regex with lookbehind or backtracking can be costly on large volumes of text).</p>

Use Cases

Validate data formats (emails, phone numbers, postal codes, IBAN)Extract structured information from raw text or logsParse and clean CSV files or poorly formatted API responsesCreate validation rules for web forms

Expected Output

A complete regular expression with a segment-by-segment explanation, a test table validating the provided examples, edge case identification, and a ready-to-use code snippet in the chosen language.

Learn more

Check the full skill on Prompt Guide to master this technique from A to Z.

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