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From: Tassilo Horn <tassilo@member.fsf.org>
Newsgroups: comp.lang.java.programmer
Subject: Re: Check if String.matches() AND (if yes) extract number from String?
Date: Mon, 21 Nov 2011 16:45:56 +0100
Organization: University Koblenz-Landau Campus Koblenz
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jochen2@brenz.com (Jochen Brenzlinger) writes:

> Assume I have a String var and value like:
>
> String var = new String("foobar[345]");
>
> Now I want to check if this string matches a certain pattern and if
> yes extract the number into a long var.

You are looking for Capturing Groups.  Have a look at
java.util.regex.Pattern and Matcher.  You need something along these
lines (untested):

        String foo = "bla[123]";
        Pattern myPattern = Pattern.compile("\\w+\\[(\\d+)\\]");
        Matcher m = myPattern.matcher(foo);
        if (m.find()) {
                long idx = Long.parseLong(m.group(1));
                // idx should be 123 here
        }

Bye,
Tassilo
-- 
(What the world needs (I think) is not
      (a Lisp (with fewer parentheses))
      but (an English (with more.)))
Brian Hayes, http://tinyurl.com/3y9l2kf