[SOLVED] Perl script to continuously compare value from lines

eminempark · 01-02-2013, 12:35 AM

I have a file called "data.txt". And inside the data file, I have briefly

Code:

PacketID 1 temperature 25
PacketID 2 temperature 26
PacketID 3 temperature 26
PacketID 4 temperature 27
PacketID 5 temperature 28
PacketID 6 temperature 28

May I know the perl script that I need to write so the result will be:

Code:

PacketID 1 temperature 25
PacketID 2 temperature 26
PacketID 4 temperature 27
PacketID 5 temperature 28

The perl script will eliminated the PacketID 3 because PacketID 2 and PacketID 3 have the same value. Same goes to PacketID 6, because it has the same value with PacketID 5.

Habitual · 01-02-2013, 09:07 AM

What have you written so far?

bijo505 · 01-02-2013, 09:22 AM

Hi Eminempark,

you can achieve this with the help of bash command it self

Code:

$ cat data.txt | sort -t " "  -k 4 -nu
PacketID 1 temperature 25
PacketID 2 temperature 26
PacketID 4 temperature 27
PacketID 5 temperature 28

if you want to use perl, you can use the following

Code:

perl -e 'system "(cat data.txt | sort -t \" \" -k 4 -un)"';
PacketID 1 temperature 25
PacketID 2 temperature 26
PacketID 4 temperature 27
PacketID 5 temperature 28

--
Thanks,
Bijo

theNbomr · 01-02-2013, 06:56 PM

So, your algorithm is intended to eliminate all records that are not unique in the second column, or just the ones that are consecutive with the record(s) immediately preceding, or.... It is impossible to know without some explanation. In part, I ask because I want to coerce you to think about the problem so that you will better learn how to solve them for yourself, or at the very least, how to compose a question about a problem.

--- rod.

eminempark · 01-03-2013, 12:25 AM

Quote:

Originally Posted by eminempark

I have a file called "data.txt". And inside the data file, I have briefly

Code:

PacketID 1 temperature 25
PacketID 2 temperature 26
PacketID 3 temperature 26
PacketID 4 temperature 27
PacketID 5 temperature 28
PacketID 6 temperature 28

May I know the perl script that I need to write so the result will be:

Code:

PacketID 1 temperature 25
PacketID 2 temperature 26
PacketID 4 temperature 27
PacketID 5 temperature 28

The perl script will eliminated the PacketID 3 because PacketID 2 and PacketID 3 have the same value. Same goes to PacketID 6, because it has the same value with PacketID 5.

Code:

$id = 0;

open FILE, "id.txt" or die $!;
while (my $line = <FILE>) {
 ($a1, $a2) = split ' ', $line;
 ($b1, $b2) = split ' ', $line;
 if ($a2 eq $b2) {
  print "$a1 $a2\n";
  $id = $a1;
 }
}
close(FILE);

But, I think the a and b variable is wrong

eminempark · 01-03-2013, 12:26 AM

Quote:

Originally Posted by theNbomr

So, your algorithm is intended to eliminate all records that are not unique in the second column, or just the ones that are consecutive with the record(s) immediately preceding, or.... It is impossible to know without some explanation. In part, I ask because I want to coerce you to think about the problem so that you will better learn how to solve them for yourself, or at the very least, how to compose a question about a problem.

--- rod.

I want to eliminate the consecutive record(s). Any idea? really need some helps...

eminempark · 01-03-2013, 12:29 AM

Quote:

Originally Posted by Habitual

What have you written so far?

Code:

$id = 0;

open FILE, "id.txt" or die $!;
while (my $line = <FILE>) {
 ($a1, $a2) = split ' ', $line;
 ($b1, $b2) = split ' ', $line;
 if ($a2 eq $b2) {
  print "$a1 $a2\n";
  $id = $a1;
 }
}
close(FILE);

But I think the variable a and b are wrong...

theNbomr · 01-03-2013, 11:50 AM

You're on the right track...

Code:

#! /usr/bin/perl -w
#
#   LQeminempark.pl
#
#   Usage: LQeminempark.pl datafile
#
#
use strict;

my $lastval = -32768;
while(<>){

    my( $tag1, $val1, $tag2, $val2 ) = split;
    if( $lastval != $val2 ){
        print $_;
    }
    $lastval = $val2;
}

--- rod.

eminempark · 01-03-2013, 08:02 PM

Quote:

Originally Posted by theNbomr

You're on the right track...

Code:

#! /usr/bin/perl -w
#
#   LQeminempark.pl
#
#   Usage: LQeminempark.pl datafile
#
#
use strict;

my $lastval = -32768;
while(<>){

    my( $tag1, $val1, $tag2, $val2 ) = split;
    if( $lastval != $val2 ){
        print $_;
    }
    $lastval = $val2;
}

--- rod.

I have run this code but it still gives me the repeated value. It doesn't eliminate any value..

theNbomr · 01-03-2013, 08:22 PM

It works for me:

Code:

$ cat LQeminempark.dat 
PacketID 1 temperature 25
PacketID 2 temperature 26
PacketID 3 temperature 26
PacketID 4 temperature 27
PacketID 5 temperature 28
PacketID 6 temperature 28

$ ./LQeminempark.pl LQeminempark.dat 
PacketID 1 temperature 25
PacketID 2 temperature 26
PacketID 4 temperature 27
PacketID 5 temperature 28

Is your sample data accurately transcribed? What happens if you copy/paste back to a datafile from the LQ posting? Maybe there is some invisible data being lost between you and LQ. Are you sure your copy of the program was accurately transcribed? Looking back at the code, I don't see anything that looks like an assumption or other trap. Maybe someone else can pinpoint a problem.

--- rod.

eminempark · 01-03-2013, 08:40 PM

Quote:

Originally Posted by theNbomr

It works for me:

Code:

$ cat LQeminempark.dat 
PacketID 1 temperature 25
PacketID 2 temperature 26
PacketID 3 temperature 26
PacketID 4 temperature 27
PacketID 5 temperature 28
PacketID 6 temperature 28

$ ./LQeminempark.pl LQeminempark.dat 
PacketID 1 temperature 25
PacketID 2 temperature 26
PacketID 4 temperature 27
PacketID 5 temperature 28

Is your sample data accurately transcribed? What happens if you copy/paste back to a datafile from the LQ posting? Maybe there is some invisible data being lost between you and LQ. Are you sure your copy of the program was accurately transcribed? Looking back at the code, I don't see anything that looks like an assumption or other trap. Maybe someone else can pinpoint a problem.

--- rod.

YEAH!!! it is working now. My command to execute it was wrong. Thank you everyone especially theNbomr...