#!C:/Perl/bin/perl -w 
#use CGI ':standard';

open (UPDATE, "update.txt") or die "Cannot open update.txt";
@data = <UPDATE>;
close (UPDATE);
#SAMPLE DATA FROM THIS ARRAY IS AS FOLLOWS:
#T00001	0123-12345	DD001	67
#T00002	0123-12345	DD001	99
#T00003	0123-12345	DD002	0
#T00008	0123-12346	DD001	76
#T00014	7777-77777	DD001	88
#T00020	0999-99999	DD001	99

open (MDF, "mdfl.txt") or die "Cannot open update.txt";
@data2 = <MDF>;
@data2 = @data2;
close (MDF);

#SAMPLE DATA FROM THIS ARRAY IS AS FOLLOWS:
#T00001	0123-12345	DD001	100	100
#T00002	0123-12345	DD001	100	100
#T00003	0123-12345	DD001	100	100
#T00004	0123-12345	DD001	100	100
#T00007	0123-12345	DD002	100	100
#T00008	0123-12346	DD001	100	100
#T00013	7777-77777	DD002	100	100
#T00014	7777-77777	DD002	100	100
#T00015	7777-77777	DD003	100	100
#T00016	8888-88888	DD001	100	100
#T00019	8888-88888	DD003	100	100
#T00020	9999-99999	DD004	100	100


#I start by reading each line fo the first array, called @data
#I split this line on tabs
		foreach $line (@data) {  
		chomp $line; 		
		@array = split (/\t/, $line);  
			$dmpiid = $array[0];				
			$be = $array[1];
			$osuf = $array[2];
			$update = $array[3];
		

#Then I read each line from the second array, splitting it on tabs too
			foreach $line2 (@data2) 
		{
			chomp $line2;
			@array2 = split (/\t/, $line2);  			
				$dmpiid2 = $array2[0];				
				$be2 = $array2[1];
				$osuf2 = $array2[2];
				$last = $array2[3];
				$curr = $array2[4];

#next I find where certain values are the same from each array

		if (($dmpiid) eq ($dmpiid2)) {

#when found, I update the appropriate values as indicated

		$last = $curr;
		$curr = $update;
		
#next, I push the following string back into the @data2 array

	$new = "$dmpiid2\t$be2\t$osuf2\t$last\t$curr\n";
        push (@data2, $new);

#next I jump out of  the inner loop because there's no need to keep checking
	
	
	last;

#however, once I do that, I need to delete the previous instance of
#the data I just updated, otherwise the array will contain both old and 
#new data...this is where I get stuck

						} #end if
		} #end inner foreach

}# end outer foreach


#this is my test which prints my results.  unfortunately, the old data is 

present allong with the new data.
foreach $item (@data2) {
print "$item\n";
}