How to split a file of 5000 lines in several files of 200 lines each with Perl? - perl

Question

I've a file of 5000 lines and I want several files of 200 lines each, and I tried this:
#!/usr/bin/perl
use strict;
use warnings;
my $targetfile = '200_lines.txt';
my $filename = '5000_lines.txt';
open ( my $DATA, '<', $filename ) or die "Could not open file '$filename': $!";
while ( my $line = <$DATA> ) {
my $counter++;
open (my $FILE, '>>', $targetfile ) or die "Could not open file '$targetfile': $!";
print $FILE $line;
close $FILE;
if ( $counter % 200 == 0
if ($. % 200 == 0) {
$targetfile =~ s/200/$counter/;
}
}
My $counter variable still at 1. I don't know why. So I got just one file named 200_lines.txt with 5000 lines.

Answer 1

You can use sprintf to generate new filenames after every 200 lines and use $. to keep track of line numbers in the file.
The below script will generate smaller chunks of files from the larger file with 200 lines each.
#!/usr/bin/perl
use strict;
use warnings;
open my $rfh,'<','file_5000' or die "unable to open file : $! \n";
my $filecount=0;
my $wfh;
while(<$rfh>){
if(($.-1) % 200 == 0){
close($wfh) if($wfh);
open($wfh, '>', sprintf("file%02d", ++$filecount)) or die $!;
}
print $wfh "$_";
}
close($rfh);

Answer 2

$counter is scoped within your while block. So it is reset each iteration.
You don't really need to do it like that, as you can test $. for the current line number
don't call your filehandle $DATA. There's a special filehandle called <DATA>.
How about:
#!/usr/bin/perl
use strict;
use warnings;
open( my $input, '<', '5000_lines.txt' ) or die $!;
open( my $output, '>', '200_lines.txt' ) or die $!;
while ( my $line = <$input> ) {
unless ( $. % 200 ) {
close($output);
open( $output, '>', int( $. / 200 + 2) . "00_lines.txt" ) or die $!;
}
print {$output} $line;
}
close($input);
close($output);
This creates files:
200_lines.txt
400_lines.txt
600_lines.txt
etc.

Answer 3

You have a bunch of errors in your code.
#!/usr/bin/perl
use strict;
use warnings;
# Creating a file with 5000 lines
my $filename = '5000_lines.txt';
open ( $DATA, '>', $filename ) or die "Could not open file '$filename': $!";
for (my $i=0;$i<5000;$i++){
print $DATA "$i\n";
}
close ( $DATA);
my $targetfile = '200_lines.txt';
open ( my $DATA, '<', $filename ) or die "Could not open file '$filename': $!";
my $counter = 0;
my $num = 0;
my $flag = 1;
while ( my $line = <$DATA> ) {
if ($flag == 1){
open (FILE, '>', $targetfile.'_'.$num ) or die "Could not open file '$targetfile.'_'.$num': $!";
}
print FILE $line;
$flag=0;
if ( $counter % 200 == 0){
$num = $counter/200;
close FILE;
$flag=1
}
$counter++;
}
close (FILE);
It will break the large file into smaller chunks of 200 lines each.