in reply to Re^2: sorting and merging in perl
in thread sorting and merging in perl

First you should show what you tried and how it failed (How do I post a question effectively?).

Replies are listed 'Best First'.
Re^4: sorting and merging in perl
by Sekhar Reddy (Acolyte) on Jul 29, 2018 at 14:37 UTC
    Below is the code, any Help Please, Thank you very much 
     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] }->{ 'INACTDA
+TE' } )

) {

$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,

    [download]

    -------I am getting error as uninitialized variable----------

    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_A
+DDON.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_A
+DDON.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

    [download]

    2018-08-02 Athanasius added code tags

[reply]
[d/l]
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      Sekhar Reddy:

      Using code tags (<c>Your code goes here</c>) would be far better than trying to manually format your code:

      • It preserves spaces, so people can see your indentation
      • It's far easier than manually inserting all those paragraph tags
      • It's less error-prone as you don't have to manually look for <, > (et. al.) and patch them up.
      • It lets the site offer a "download" button to let people more easily grab your code

      If you had used code tags, it would look more like the following:

      use Data::Dumper;

my %results = ();
while ( <DATA> ) {
    chomp;
    my @row = split /,/, $_;
    print STDOUT "row values is:".$_."\n";
    if ( (exists $results{ $row[0], $row[1] })) {
        if ( ( $row[2] ) <
                $results{ $row[0], $row[1] }->{ 'ACTDATE' }
        ) {
            $results{ $row[0],$row[1] }->{ 'ACTDATE' } = $row[2] ;
        }
        print STDOUT "inactdate--".$row[3]." \n";
        print STDOUT "in memory inact--".$results{ $row[0] }->{ 'INACT
+DATE' }."\n";
        if ( ( defined $row[3]) && !( defined $results{ $row[0] }->{ '
+INACTDATE' } )
        ) {
            $results{ $row[0] }->{ 'INACTDATE' } = undef ;
        }

      [download]

      Obviously not exactly like that, as I don't know how your code is normally formatted, nor did I bother to clean up the whole thing.

      OK, for the errors you're encountering: I'd suggest you start looking at how you're accessing the data items you're putting in results. You're storing some items into the hash like this:

          $results{ $row[0], $row[1] } = {
        'A1' => $row[0],
        'B1' => $row[1],
        'ACTDATE' => $row[2],
        'INACTDATE' => $row[3],
    }

      [download]

      but you're sometimes referring to them like:

          $results{ $row[0],$row[1] }->{ 'ACTDATE' }

      but at other times you're doing things like:

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

      I expect the mismatched hash keys are the reason that you're getting all the "uninitialized value warnings. Clean that up and that will probably get you closer to your desired result.

      ...roboticus

      When your only tool is a hammer, all problems look like your thumb.

[reply]
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[select]
      roboticus did identify the error in the code you posted.

      The code you posted is (with some minor changes).

      Split the line into 4 named variables instead of @row (makes the problem clearer).

      Eliminate quoting keys to the hash when they exist of all word characters (so don't need to be quoted). 

      #!/usr/bin/perl
use strict;
use warnings;

my %results;
open my $fh, '<', 'file1.csv' or die $!;

while ( <$fh> ) {
    chomp ;
    my ($a1, $b1, $actDt, $inactDt) = split /,/;
    
    if (exists $results{$a1,$b1} ) {
    
        if ($actDt < $results{$a1,$b1}{ACTDATE}) {
            $results{$a1,$b1}{ACTDATE} = $actDt;
        }
            
        if (!$inactDt || !$results{$a1,$b1}{INACTDATE}) {
            $results{$a1,$b1}{INACTDATE} = '' ;
        }
        elsif($inactDt > $results{$a1,$b1}{INACTDATE} ) {
            $results{$a1,$b1}{INACTDATE} = $inactDt;
        }
    }
    else {  
        # Create new entry in hash
        $results{$a1,$b1} = {
            A1 => $a1,
            B1 => $b1,
            ACTDATE => $actDt,
            INACTDATE => $inactDt,
        };
    }
}
    
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" ;
}

      [download]
      The output gives erroneous results because you include non-contiguous records. The output with is: 
      7900724655,200906888,20180416,20180830
7900724655,200906889,20180601,20180728
7900724655,200906890,20180905,
7900724666,200906868,20180416,20180830
7900724666,200906869,20180601,20180728
7900724666,200906890,20180905,

      [download]

      To get the results you want doesn't require a hash. 

      #!/usr/bin/perl
use strict;
use warnings;

open my $fh, '<', 'file1.csv' or die $!;

my ($actDt, $inactDt, $count) = ('', '', 0);
my $previous_key = '';

while (<$fh>) {
    chomp;
    my ($a1, $b1, $begin, $end) = split /,/;
    my $key = "$a1,$b1";
    
    if ($previous_key eq $key) {
        $inactDt = $end;
        $count++;
    }
    else { # either reached the end of a record or this is the first r
+ecord
        print join(",", $previous_key, $actDt, $inactDt), "\n"
            if $count > 1;
        $actDt = $begin;
        $inactDt = $end;
        $count = 1;
    }
    $previous_key = $key;
}

print join(",", $previous_key, $actDt, $inactDt), "\n"
    if $count > 1;

      [download]
      This gives the desired results: 
      7900724655,200906889,20180601,20180728
7900724655,200906890,20180905,
7900724666,200906869,20180601,20180728
7900724666,200906890,20180905,

      [download]
      The input file is: 
      7900724655,200906888,20180416,20180522
7900724655,200906889,20180601,20180720
7900724655,200906889,20180724,20180728
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,

      [download]
[reply]
[d/l]
[select]

        Hi Athanasius,

        First of all thank you very much for your try. I tried with your code, but still that is also giving some incorrect results. Below fyi.

        Input data that i have considered below

        7900724666,200906888,20180416,20180522
7900724666,200906888,20180601,20180720
7900724666,200906888,20180406,20180411
7900724677,200906872,20180301,20180330
7900724677,200906871,20180101,20180228
7900724677,200906873,20180401,20180420
7900724688,200906881,20180101,20180228
7900724688,200906881,20180303,20180330
7900724688,200906882,20180404,20180430
7900724688,200906883,20180508,20180620
7900724699,200906891,20180101,20180228
7900724699,200906891,20180303,20180330
7900724699,200906892,20180404,20180430
7900724699,200906893,20180508,
7900724611,200906888,20180416,20180522
7900724611,200906889,20180724,20180728
7900724611,200906889,20180601,20180720
7900724611,200906888,20180730,20180830
7900724611,200906890,20180905,20180930
7900724611,200906890,20181005,20181030
7900724611,200906890,20181104,
7900724622,200906868,20180416,20180522
7900724622,200906869,20180601,20180720
7900724622,200906869,20180724,20180728
7900724622,200906868,20180730,20180830
7900724622,200906890,20180905,20180930
7900724622,200906890,20181005,20181030
7900724622,200906890,20181104,

        [download]

        The output which i have got is below

        7900724666,200906888,20180416,20180411
7900724688,200906881,20180101,20180330
7900724699,200906891,20180101,20180330
7900724611,200906889,20180724,20180720
7900724611,200906890,20180905,
7900724622,200906869,20180601,20180728
7900724622,200906890,20180905,

        [download]

        Here 1st line and 4th line in output are incorrect: Ex: 

        7900724611,200906889,20180724,20180720

        [download]

        Here expected result in output 4th line is 7900724611,200906889,20180601,20180728

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