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From: Knute Johnson <eternal@knutejohnson.com>
Newsgroups: comp.lang.java.programmer
Subject: Re: regex puzzle
Date: Wed, 09 Apr 2014 18:24:32 -0700
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On 4/9/2014 16:24, Roedy Green wrote:
> On Wed, 09 Apr 2014 16:14:45 -0700, Roedy Green
> <see_website@mindprod.com.invalid> wrote, quoted or indirectly quoted
> someone who said :
>
>> nope  1|2|3|4|5|6|7|8|9|10|11|12|13|14|15|16|17|18|19|20
>>
>> hopefully a little more terse.
>>
>> and would not match  2099
>
> I think you need a new regex operator that collects characters 0-9,
> 0-9\. etc then parses a number, then compares it with low and high
> bound in the regex operator.
>
> It seems like such a simple problem.
>
> Regex gets foiled so easily, like parsing HTML tags when they don't
> appear in canonical order.
>

import java.util.regex.*;

public class test5 {
     public static void main(String[] args) {
         String sequence = "1..20";
         String subject = "1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 
19 20";

         System.out.println(matchSeq(sequence,subject) ? "matches" : "no 
match");
     }

     public static boolean matchSeq(String seq, String subject) {
         Pattern p1 = Pattern.compile("(\\d+)\\.\\.(\\d+)");
         Matcher m1 = p1.matcher(seq);
         if (m1.matches()) {
             int from = Integer.parseInt(m1.group(1));
             int to = Integer.parseInt(m1.group(2));
             String s2 = Integer.toString(from);
             for (int i=from+1; i<=to; i++)
                 s2 = s2.concat(String.format(" %d",i));
             Pattern p2 = Pattern.compile(s2);
             Matcher m2 = p2.matcher(subject);
             return m2.matches();
         } else {
             throw new IllegalArgumentException("bad sequence");
         }
     }
}



-- 

Knute Johnson