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  • Regular Expressions 101

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GeezerVison is showing regex101.com — regex101: Online Regex Tester, Builder, Converter & Debugger

/ ^ r e g e x [ \ - _ ] ? 1 0 1 $ / i

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MatchSubstitutionExtractionUnit Tests

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Explanation
Pro

Understand your regular expression with explanations of its tokens, groups, and flags. Regex conversion adapts patterns, flags, and replacements across flavors and explains compatibility changes.

Refine regexes faster with . Turn examples into patterns, fix mismatches, and build tests to check your changes.

Supports:
  • PCRE2 (PHP)
  • JavaScript
  • Python
  • Golang
  • Java
  • .NET 10.0 (C#)
  • Rust
  • POSIX ERE
  • POSIX BRE (grep/sed)
  • PCRE (Legacy)

Match Information

See what matched and what each group captured, including named groups and values reusable in replacements or backreferences. Investigate unexpected results with the regex debugger and export them to JSON, JSON Lines, CSV, or Plain Text afterwards.

Quick Reference

25 tokens

Regular Expression

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