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Checking for a simple pattern in a String

Posted on 2004-09-04
9
229 Views
Last Modified: 2010-03-31
I am writing a text parser and I want to be able to detect extracts of text that are in the following pattern

XX1234

e.g 2 Capital Letters, followed by 4 numbers

What would be the best way to do this?

Cheers

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Question by:chocobogo
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9 Comments
 
LVL 3

Accepted Solution

by:
mte01 earned 100 total points
ID: 11979556
The following code will do the trick (although it is better to use Lex & Yacc parsing utilities:


   String teststring = new String("Anything that has AA1234 or CF3654");
    String[] foundstring = new String[10];
    int found = 0,j=0;
    for(int i=0;i<=teststring.length();i++)
    {
        if(found < 2)
        {
          if(teststring.charAt(i) >= 'A' && teststring.charAt(i) <= 'Z')
            found++;
          else
          {
            found = 0;
            continue;
          }
        }
        else if(found >= 2 && found < 6)
        {
          if(teststring.charAt(i) >= '0' && teststring.charAt(i) <= '9')
            found++;
          else
          {
            found = 0;
            continue;
          }
        }
        else if(found==6)
        {
          foundstring[j++] = teststring.substring(i-6,i);
          found=0;
        }
      }
      for(int i=0;i<j;i++)
      {
        System.out.println(foundstring[i]);
      }

0
 

Author Comment

by:chocobogo
ID: 11979582
Cheers dude!
I will work with the code above & look into  Lex & Yacc for the future!

0
 
LVL 14

Expert Comment

by:sudhakar_koundinya
ID: 11979583
Probably this will help you



import java.util.*;
class  SearchText
{
      public static void main(String[] args)
      {
               String str="AA12442AA678889AB67678AA3333AZ6767YT7878FG4559";

               Vector vect=new Vector();
               for(int i=0;i<str.length();i++)
            {
                        try
                        {
                              String str1=str.substring(i,i+2);
                              String str2=str.substring(i+2,i+6);

                              if(str1.length()==2 && str2.length()==4)
                              {

                                       if(str1.matches("[A-Z]*") && str2.matches("[0-9]*"))
                                          {

                                             vect.add(str1+str2);
                                          }
                              }
                        }
                        catch(Exception ex)
                        {
                              
                        }
            }
            for(int i=0;i<vect.size();i+=1)
            {
                  System.err.println(vect.get(i));
            }

      }
}

Regards
Sudhakar
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Expert Comment

by:sudhakar_koundinya
ID: 11979586
May be I am late but pattern matching is best for such operations :)
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Expert Comment

by:zzynx
ID: 11979589
Regular expressions can help

System.out.println( "sef<DE1245>6fq<PF0047>sfgsfd".
                            replaceAll("([ABCDEFGHIJKLMNOPQRSTUVWXYZ]){2}([1234567890]){4}", "######" ) );

This prints:

sef<######>6fq<######>sfgsfd

Now in the resulting string you search for all occurrences of "######" with indexOf().
The indices returned by indexOf are the ones that can be used in the original string.
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LVL 14

Expert Comment

by:sudhakar_koundinya
ID: 11979590
>> String[] foundstring = new String[10];

Take care about this

 String[] foundstring = new String[str.length()/6]; may save you  where str is ur main string
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LVL 37

Expert Comment

by:zzynx
ID: 11979591
Whoops accepted already...
0
 
LVL 14

Expert Comment

by:sudhakar_koundinya
ID: 11979599
String[] foundstring = new String[str.length()/6+1]; may save you  where str is ur main string
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Author Comment

by:chocobogo
ID: 11980186
cheers for all the extra comments guys !!
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