Programming Crystal

Using Regular Expressions

Sometimes you want the flexibility of strings, but you need to process them efficiently. Searching and replacing inside of strings can also use a lot of processing cycles. Regular expressions, or regexes, can reduce the costs of string processing substantially thanks to highly optimized processing models. Crystal uses the PCRE syntax.^[30] This is implemented as a C binding to the PCRE C-library. (Though Ruby uses a different regex engine, it also uses PCRE syntax.)

Patterns are usually created with the /pattern/ literal syntax. If you have a regex that includes a slash you don’t want to have to escape, you can also create a pattern with %r(pattern). Once you have a pattern, you can apply it to strings. Use =~ or the ...