use warnings ;

use Data::Dumper;

my %results = ();

while ( <DATA> ) {

chomp ;

my @row = split /,/, $_ ;

print STDOUT "row values is:".$_."\n";

if ( (exists $results{ $row[0], $row1 })) {

if ( ( $row2 ) <

$results{ $row[0], $row1 }->{ 'ACTDATE' }

) {

$results{ $row[0],$row1 }->{ 'ACTDATE' } = $row2 ;

}

print STDOUT "inactdate--".$row3." \n";

print STDOUT "in memory inact--".$results{ $row[0] }->{ 'INACTDATE' }."\n";

if ( ( defined $row3) && !( defined $results{ $row[0] }->{ 'INACTDATE' } )

) {

$results{ $row[0] }->{ 'INACTDATE' } = undef ;

}

elsif ( !( defined $row3) && ( defined $results{ $row[0] }->{ 'INACTDATE' } )

) {

$results{ $row[0] }->{ 'INACTDATE' } = undef ;

}

elsif( ( $row3 ) > ( $results{ $row[0], $row1 }->{ 'INACTDATE' } ) )

{

$results{ $row[0], $row1 }->{ 'INACTDATE' } = $row3;

}

} else {

# Create new entry in hash

$results{ $row[0],$row1 } = {

'A1' => $row[0],

'B1' => $row1,

'ACTDATE' => $row2,

'INACTDATE' => $row3,

}

}

}

foreach ( sort keys %results ) {

my $a1 = $results{ $_ }->{ 'A1' } ;

my $b1 = $results{ $_ }->{ 'B1' } ;

my $actDt = $results{ $_ }->{ 'ACTDATE' } ;

my $inactDt = $results{ $_ }->{ 'INACTDATE' };

print "$a1,$b1,$actDt,$inactDt\n" ;

}

__DATA__

7900724655,200906888,20180416,20180522

7900724655,200906889,20180724,20180728

7900724655,200906889,20180601,20180720

7900724655,200906888,20180730,20180830

7900724655,200906890,20180905,20180930

7900724655,200906890,20181005,20181030

7900724655,200906890,20181104,

7900724666,200906868,20180416,20180522

7900724666,200906869,20180601,20180720

7900724666,200906869,20180724,20180728

7900724666,200906868,20180730,20180830

7900724666,200906890,20180905,20180930

7900724666,200906890,20181005,20181030

7900724666,200906890,20181104,

##</code><code>##

row values is:7900724655,200906888,20180416,20180522
row values is:7900724655,200906889,20180724,20180728
row values is:7900724655,200906889,20180601,20180720
inactdate--20180720
Use of uninitialized value in concatenation (.) or string at web_New_ADDON.pl line 16, <DATA> line 3.
in memory inact--
row values is:7900724655,200906888,20180730,20180830
inactdate--20180830
Use of uninitialized value in concatenation (.) or string at web_New_ADDON.pl line 16, <DATA> line 4.
in memory inact--
row values is:7900724655,200906890,20180905,20180930
row values is:7900724655,200906890,20181005,20181030
inactdate--20181030