capture string that matches regex

[Tyler Jordan]

I'm looking for a way to capture a string out of a larger string that matches a regex. I looked into the String class, but there is nothing there to help. I can't believe a function like this isn't included in the class. I can match on it, but can't extract it:

ie.

String myRegex = "^[U||C]J[A-Z]{5}[0-9]{3}$"
String myString = "blah blahblah UJABCDE999 blah blah blah"

Any ideas?

[Stevi Deter]

Tyler,

I think you're looking for the Pattern and Matcher classes. Check the Java Tutorial.

It seems a fine separation of concerns that String doesn't know how to apply regular expressions to itself.

[Tyler Jordan]

Thanks! The function group() from matcher fits the bill.

[Alan Moore]

Originally posted by Tyler Jordan:
Thanks! The function group() from matcher fits the bill.

But your regex doesn't. The '^' and '$' anchors force the regex to match the entire string, but you obviously want to pluck out matching substrings. Also, there's no need for the "||" (or even "|") in the first character class; OR is implicit, and in fact a pipe just matches a pipe when you use it in a character class. Putting it all together:

Pattern p = Pattern.compile("[UC]J[A-Z]{5}[0-9]{3}");
Matcher m = p.matcher(str);
while (m.find())
{
  String found = m.group();
  // etc.
}

[Rob Spoor]

This thread has almost exactly the same question but has some more info, so let's continue there.