Regular expressions in simple terms is a pattern that can be matched against a string. With regular expression you can test a string to check if it matches a pattern, or you can change the entire string replacing its certain parts that matches a pattern or you can also extract from a string the section that matches a pattern.
In Ruby we write regular expression literal in between forward slashes. For example, /ruby/ is a regular expression literal.
so /ruby/ matches “i love ruby language” string. To match a special character, we have to precede it with a backslash. So /\// is a pattern that matches forward slash.
Ruby uses =~ to match a pattern with a string. This returns the offset of the character at which the match occurred.
For example,
/ruby/ =~ "i love ruby language" => 7 /matz/ =~ "matz is an awesome person" => 0
When the pattern matching fails, it will return a nil.
For a detailed explanation on Ruby’s regular expression, I would recommend Programming Ruby 1.9
Jus check this also, cheat sheet for regular expression http://goo.gl/TeKW . This also hepls sometimes.
srihari » January 16, 2011
Hey , have you seen http://rubular.com , where you can try out your regexps .