主题： regex

• Regex flavors: BRE/ERE, PCRE2, RE2, JavaScript, Python and .NET side by side

  The characters + ? | ( ) { } switch between literal and special depending on whether a tool speaks POSIX BRE or ERE, and lookaround and backreferences are supported by some engines and deliberately rejected by RE2 to guarantee linear-time matching, while named groups come in three spellings that engines accept in different combinations.

  article · en · reviewed · 知识截至 2026-09-25

机器可读： JSON