Programming Ruby 3.3

Creating and Using Regular Expressions

Ruby has many ways of creating a regular expression pattern. By far, the most common is to write the pattern between forward slashes. Thus, the pattern /cat/ is a regular expression literal in the same way that "cat" is a string literal.

/cat/ is an example of a simple pattern. It matches any string that contains the substring cat. In fact, inside a regular expression pattern, all characters except ., |, (, ), [, ], {, }, +, \, ^, $, *, and ? match themselves. So, at the risk of creating something that sounds like a logic puzzle, here are some patterns and examples of strings they match and don’t match:

/cat/	Matches "dog and cat" and "catch" but not "Cat" or "c.a.t."
/123/	Matches "86512312" and