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From: Robert Klemme <shortcutter@googlemail.com>
Newsgroups: comp.lang.java.programmer
Subject: Re: simple regex pattern sought
Date: Sat, 26 May 2012 00:12:34 +0200
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On 25.05.2012 23:55, Lew wrote:
> Roedy Green wrote:
>> I often have to search for things of the form
>>
>> "xxxxx"
>> or
>> 'xxxxx'
>>
>> where xxx is anything not " or '.  It might be Russian or English or
>> any other language.
>>
>> What is the cleanest way to do that?
>
> Use a regex like "[\"'][^\"']+[\"']" is one way. The cleanest? I don't know.

That does not match quoting properly.  Better do something like

"([\"'])[^\"']*\\1"

Still I prefer

"\"[^\"]*\"|'[^']*'"

Because it allows for quotes of the other type inside quotes.

With proper escaping (using \ as escape char, any other works, too) this 
becomes

"\"(?:\\\\.|[^\\\"])*\"|'(?:\\\\.|[^\\'])*'"

Kind regards

	robert


package rx;

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class Quotes {

   private static final Pattern Q1 = Pattern.compile("([\"'])[^\"']*\\1");
   private static final Pattern Q2 = Pattern.compile("\"[^\"]*\"|'[^']*'");
   private static final Pattern Q3 = 
Pattern.compile("\"(?:\\\\.|[^\\\"])*\"|'(?:\\\\.|[^\\'])*'");

   public static void main(String[] args) {
     System.out.println(Q1);
     for (final Matcher m = Q1.matcher("'a' \"b\" 'c'"); m.find();) {
       System.out.println(m.group());
     }

     System.out.println(Q2);
     for (final Matcher m = Q2.matcher("'a' \"b\" 'c'"); m.find();) {
       System.out.println(m.group());
     }

     System.out.println(Q3);
     for (final Matcher m = Q3.matcher("'a' \"\\\"b\" 'c'"); m.find();) {
       System.out.println(m.group());
     }
   }

}


-- 
remember.guy do |as, often| as.you_can - without end
http://blog.rubybestpractices.com/