#!/usr/local/bin/perl 

use strict;

open (FILE1,"Largedatafile.txt") || die "Can't open file File1 $!\n";
open (FILE2,"Smalldatafile.txt") || die "Can't open file File2 $!\n";
open (FILE3,"addressfile.txt") || die "Can't open file File3 $!\n";

  while(<FILE2>)
  {
  my($var1, $var2, $var3,$var4,$var5)=split(/\t/, $_);
     
       while(<FILE1>)
       {
       my($id1, $id2,$id3)=split(/\t/,$_);
        
         while(<FILE3>)
         {
                my($citycode, $statecode,$zipcode)=split(/\t/,$_);
        
                 if (($id3 ne $var3) and ($citycode ne $var5))
                 {
                        print "$var1\t$id1\t$zipcode\n";    
                        }
         }  
       }
  }

close (FILE1);
close (FILE2);
close (FILE3);
[download]

input file1 "Largedatafile.txt"

new_id        county_name1  county_id1     routing_number     city_cod
+e1
56897987     Smith                  865487          567rt9834         
+        5879654
65798686     Johnson             6587654          6578ce789           
+  r6587t3
24598702     Rock                  6548365          6456t6884         
+      z0rt345
[download]

input file2 "Smalldatafile.txt"

Old_id          state_code2      fip_code
865487234    5679834              5879654
6587654098  6578789              43658753
6548365tr     6456884              50054345
[download]

input file3 "addressfile.txt"

city_code3         state_code3      zip_code3
5879654              5679834              987656575
r658735               6578789               657656315
z0r3454               6456884               554865434

</c
<p>
out put file will have new_id from file1, old_id from file2, and 
zip_code3 from file3 only if state_code2 from file2 not equal to state
+_code3 from file3 and city_code3 from file 3 not equal to city_code1 
+form file1
</p><p>

after running the script I do not get the value of  "Old_id" and  "cit
+y_code3"
</p>
<c>

new_id    Old_id  zip_code3

new_id    Old_id  987656575

new_id    Old_id  657656315

new_id    Old_id  554865434

new_id    Old_id  987656575

new_id    Old_id  657656315

new_id    Old_id  554865434
[download]

20060712 Janitored by Corion: Added code tags, as per Writeup Formatting Tips and Writeup Formatting Tips

Okay, first: update your posts by adding <code> at the beginning of the perl script, and </code> at the end of the perl script. Just do it. Likewise for sample data.

Second: when you do this:

open( FILE1, ... );
open( FILE2, ... );
open( FILE3, ... ):

while (<FILE1>) {
   ...
   while (<FILE2>) {
      ...
      while (<FILE3>) {
         ...
      }
   }
}
[download]

FILE2 and FILE3 will both reach EOF during the first iteration on (the first line read from) FILE1. So don't do that.

(You could "seek( FILE3, 0, 0 );" at the end of the while loop that reads from FILE2, and also do "seek( FILE2, 0, 0 );" at the end of the loop that reads from FILE1, but this would mean that you re-read FILE2 too many times, and you re-read FILE3 way too many times. So don't do that.)

Since FILE2 is "small" and FILE3 is probably not too big either, read them both into hash structures first to keep them in memory while you read the "large" file. When loading the hashes with data in these two files, the hash keys should be the strings you need for linking data across files, and the values should be whatever you need to keep from each file for your final output.

Third: you said

output file will have new_id from file1, old_id from file2, and zip_code3 from file3 only if state_code2 from file2 not equal to state_code3 from file3 and city_code3 from file 3 not equal to city_code1 from file1

This statement really does not make sense, unless you seriously want the "cartesian product" of all the lines in the three files. That is, supposing there are 100 lines in "largefile", 10 lines in "smallfile" and 20 lines in "addressfile", and there are some matches among the city_code and state_code values, then the condition as you phrased it would list about 99*9*19 lines of output.

Do you mean something like this instead?

OUTPUT file1:new_id, file2:old_id, file3:zip_code3
 IF file1:city_code1 DOES NOT MATCH ANY file3:city_code3
  OR ( file1:city_code1 MATCHES ONE file3:city_code3
      AND THIS file3:state_code3 DOES NOT MATCH ANY file2.state_code2 
+)
[download]

If that's not what you mean, then you really need to explain it better. Given just the snippets of sample data that you have shown, what should the output be? (If those snippets would not really produce any outputs, because everything matches up, add a row or two that would generate the intended output, and show us what the output should be.) And remember to use "code" tags.

In any case, it sounds like some sort of SQL problem, and it looks like your data came from a database (or could easily be put into a database). So maybe SQL would be the more prudent approach. (But proper use of hashes to store the relevant stuff from the two smaller files would do fine.)