RE2 is a fast, safe, thread-friendly alternative to backtracking regular expression engines like those used in PCRE, Perl, and Python. It is a C++ library.
RE2 provides pattern matching, extraction, replacement and other string processing operations using Google's RE2 (C++) regular-expression library.
RE2 differs slightly from PCRE. For example, regular expressions are case-sensitive by default.
Webmasters will commonly use RE2 when using Google services such as Google Analytics, Google Search Console, and Google Data Studio. It is also the regex engine used by the Go Programming Language.
