How to extract a substring using regex

Question

I have a string that has two single quotes in it, the \' character. In between the single quotes is the data I want.

How can I write a regex to extract

Answer 1

Since Java 9

As of this version, you can use a new method Matcher::results with no args that is able to comfortably return Stream where MatchResult represents the result of a match operation and offers to read matched groups and more (this class is known since Java 1.5).

String string = "Some string with 'the data I want' inside and 'another data I want'.";

Pattern pattern = Pattern.compile("'(.*?)'");
pattern.matcher(string)
       .results()                       // Stream
       .map(mr -> mr.group(1))          // Stream - the 1st group of each result
       .forEach(System.out::println);   // print them out (or process in other way...)

The code snippet above results in:

the data I want
another data I want

The biggest advantage is in the ease of usage when one or more results is available compared to the procedural if (matcher.find()) and while (matcher.find()) checks and processing.