Small regexp tip
To find the shortest match in a using using regular expressions you can use a "Reluctant" qualifier like ".+?" instead of simply ".+" (greedy qualifier) which will find the longest match.
Wow - did that make my day!! :-)
Re: Small regexp tip
No I actually mean it as a write it - consider some input such as:
Section Contents1 End Section Section Contents2 End Section
If I wanted to use regexp to split the input into two parts with a section in each I would need to use ".+?" and not ".+" to indicate the actual contents between the "Section" and "End Section" parts. If I do the result will be what you expect. I a don't the result will only be a single match with the entire input.
Try running the below code:
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class Lekkim {
public static void main(String[] args) {
String input = "Section\n Contents1\nEnd Section\n" +
"\nSection\n Contents2\nEnd Section\n";
Pattern p1 = Pattern.compile("(Section.+End Section)", Pattern.DOTALL);
Pattern p2 = Pattern.compile("(Section.+?End Section)", Pattern.DOTALL);
System.out.println("Input is:\n" + input);
System.out.println("*** *** *** *** ***");
Matcher m = p1.matcher(input);
while (m.find()) {
System.out.println("Match:\n" + m.group());
}
System.out.println("*** *** *** *** ***");
m = p2.matcher(input);
while (m.find()) {
System.out.println("Match:\n" + m.group());
}
}
}
Re: Small regexp tip
I ran into problems with reluctant qualifiers recently - it seems as if older versions of Python did not implement regex properly. It nearly drove me nuts trying to figure out what was going on. That being said, once I found out about them I went about happily revising old code...