The Book of Ruby

MatchData

The =˜ operator is not the only means of finding a match. The Regexp class also has a match method. This works in similar way to =˜, but when a match is made, it returns a MatchData object rather than an integer. A MatchData object contains the result of a pattern match. At first sight, this may appear to be a string.

match.rb

puts( /cde/ =˜ 'abcdefg' )        #=> 2
puts( /cde/.match('abcdefg') )    #=> cde

In fact, it is an instance of the MatchData class that contains a string:

p( /cde/.match('abcdefg') )       #=> #<MatchData: "cde" >

A MatchData object may contain groups, or captures, and these can be returned in an array using either the to_a or captures method, like this:

matchdata.rb

x = /(^.*)(#)(.*)/.match( 'def myMethod # This is a very nice method' ...