How to match all occurrences of a regex

Question

Is there a quick way to find every match of a regular expression in Ruby? I've looked through the Regex object in the Ruby STL and searched on Google to no avail.

Answer 1

Using scan should do the trick:

string.scan(/regex/) 

Answer 2

To find all the matching strings, use String's scan method.

str = "A 54mpl3 string w1th 7 numb3rs scatter36 ar0und" str.scan(/\d+/) #=> ["54", "3", "1", "7", "3", "36", "0"] 

If you want, MatchData, which is the type of the object returned by the Regexp match method, use:

str.to_enum(:scan, /\d+/).map { Regexp.last_match } #=> [#<MatchData "54">, #<MatchData "3">, #<MatchData "1">, #<MatchData "7">, #<MatchData "3">, #<MatchData "36">, #<MatchData "0">] 

The benefit of using MatchData is that you can use methods like offset:

match_datas = str.to_enum(:scan, /\d+/).map { Regexp.last_match } match_datas[0].offset(0) #=> [2, 4] match_datas[1].offset(0) #=> [7, 8] 

See these questions if you'd like to know more:

• "How do I get the match data for all occurrences of a Ruby regular expression in a string?"
• "Ruby regular expression matching enumerator with named capture support"
• "How to find out the starting point for each match in ruby"

Reading about special variables $&, $', $1, $2 in Ruby will be helpful too.