Perl - Comparison of Files using specific substrings - perl

Question

i ve writted thsi script to compare lines of two files, and output common/not common lines into two different files. The script is :
use strict;
use warnings;
use autodie;
my $f1 = shift || "CSP8216.TXT";
my $f2 = shift || "CSP8217.TXT";
open my $fh1, '>', 'file1';
open FH2, '>', 'file2';
my %results;
open my $file1, '<', $f1;
while (my $line = <$file1>) {
$results{$line} = 1
}
open my $file2, '<', $f2;
while (my $line = <$file2>) {
$results{$line}++
}
foreach my $line (sort { $results{$b} <=> $results{$a} } keys %results)
{
if ($results{$line} >= 1)
{
print {$fh1} "$line";
}
else
{
print FH2 "$line";
}
}
My problem is when i try to mod this script but run the comparisons based on specific substrings of each line, ie :
If a specific substring of a line of file A matches another specific substring of a line in File B, then output said /entire/ line of File B into fh1, otherwise output it into fh2.
I tried this, but it doesnt work - really new to Perl still, any help will be really appreciated :
use strict;
use warnings;
use autodie;
my $f1 = shift || "CSP8216.TXT";
my $f2 = shift || "CSP8216.TXT";
open my $fh1, '>', 'file1';
open FH2, '>', 'file2';
my %results;
open my $file1, '<', $f1;
while (my $line = <$file1>)
{
my $sbs1 = substr($line, 0, 10);
$results{$sbs1} = 1
}
open my $file2, '<', $f2;
while (my $line = <$file2>)
{
my $sbs2 = substr($line, 0, 10);
$results{$sbs2}++
}
foreach my $line (sort { $results{$b} <=> $results{$a} } keys %results)
{
if ($results{$line} >= 1)
{
print {$fh1} "$line";
}
else
{
print FH2 "$line";
}
}
This does not work, and i have a feeling its a problem in the logic, it outputs just the substrings in a single line.

Answer 1

As per my comment, we need to keep the lines from file A and file B separate if we need to support that a single line can appear twice in one file.
On option is to solve the basic problem like this
open my $fh1, '<', $filename1 or die "Can't open $file1: $!";
while (my $line = <$fh1>) {
$combined{$line} = $file1{$line} = 1;
}
open my $fh2, '<', $filename2 or die "Can't open $file2: $!";
while (my $line = <$fh2>) {
$combined{$line} = $file2{$line} = 1;
}
open my $out1, '>', $outfilename1 or die "...";
open my $out2, '>', $outfilename2 or die "...";
for my $line (keys %combined) {
if ($file1{$line} && $file2{$line}) {
print $out1 $line;
} else {
print $out2 $line;
}
}
To solve the substring issue I would keep the substrings from each file as keys in the hashes. But instead of just storing the true value I would store the full string as value in %file2:
open my $fh1, '<', $filename1 or die "Can't open $file1: $!";
while (my $line = <$fh1>) {
my $substr = substr($line, 0, 10);
$combined{$line} = $file1{$substr} = 1;
}
open my $fh2, '<', $filename2 or die "Can't open $file2: $!";
while (my $line = <$fh2>) {
my $substr = substr($line, 20, 30);
$combined{$line} = 1;
$file2{$substr} = $line;
}
open my $out1, '>', $outfilename1 or die "...";
open my $out2, '>', $outfilename2 or die "...";
for my $line (keys %combined) {
my $substr1 = substr($line, 0, 10);
my $substr2 = substr($line, 20, 30);
if ($file1{$substr1} && $file2{$substr2}) {
print $out1 $file2{$substr2};
} else {
print $out2 $line;
}
}

Answer 2

This works for me
#!/usr/bin/perl
use warnings;
use autodie;
my %results;
my $f1 = shift || "CSP8216.TXT";
my $f2 = shift || "CSP8217.TXT";
open my $fh1, '>', 'file1';
open my $fh2, '>', 'file2';
open my $file1, '<', $f1;
while (my $line = <$file1>) {
my $sbs1 = substr($line, 0, 10);
$results{$sbs1} = 1
}
open my $file2, '<', $f2;
while (my $line = <$file2>) {
my $sbs2 = substr($line, 0, 10);
if (!$results{$sbs2}) {
$results{$sbs2} = 1;
}
$results{$sbs2}++
}
foreach my $line (sort { $results{$b} <=> $results{$a} } keys %results) {
if ($results{$line} > 1) {
print {$fh1} "$line";
}
else {
print {$fh2} "$line";
}
}