A list of capturing and non-capturing groups avaiable in regular expressions

README.md

Groups in regular expressions (Capturing and non-capturing)

In regular expressions groups can be used. Different types of groups have different notations.

These notations sometimes only differ as little as one character. This can be confusing.

To make it easier to distinguish between the different group types, they are all listen here.

Overview

The following groups are available in Regular expressions:

• (…) Capturing group and (?<…>…) named capturing group
• (?:…) Non-capturing group
• (?!…) Negative Lookahead
• (?=…) Positive Lookahead
• (?<!…) Negative Lookbehind
• (?<=…) Positive Lookbehind

Lookahead and lookbehind are also non-capturing groups. Together they are known as "lookarounds".

regular-expression-groups.pegjs

group 
  = "(" 
    ( 
      / "?" 
      (
        "<" "…" ">" /* named capturing group */
        / ":" /* Non-capturing group */
        / "<"? /* Lookbehind */
          (
            "!" /* Negative Lookahead / Lookbehind */
            / "=" /* Positive Lookahead / Lookbehind */
          )
      )
    )
    "…" 
    ")"
  ;

regular-expression-groups.svg

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</svg>