Perl modifying CSV files - perl

Question

I have a small section of code I'm trying to modify.
What I'm trying to do is have the filename inputted into the third column. At the moment I almost have it working, but I'd like to remove the ".csv"s from the end of each entry in the column. I'd also like to give the column the heading "filename".
I hope the difference between "table1" and "table2" shown above summarises quite well the modification which I'm trying to make here.
The code I'm currently using to create "table1" is the following:
#!/usr/bin/perl
use warnings;
use strict;
open M,"<mapcodelist.txt" or die "mapcodelist.txt $!";
my %m;
while( <M> ){
my($k,$v)=split;
$v=~s/\./_/g;
$m{$k}=$v;
}
close M;
chdir "C:/Users/Stephen/Desktop/Database_Design/" or die $!;
#ARGV=<*.csv>;
$^I=".bak";
while( <> ){
chomp;
$\=/^mass/?",filename$/": ",$ARGV$/";
print;
}
for( <*.csv> ){
my $r;
($r=$_) =~ s/\w+_(\w+)(?=\.csv)/$1_$m{$1}/;
rename $_,$r or warn " rename $_,$r $!";
}
Any advice with this would be very much appreciated.
Thanks.

Answer 1

You can try following perl script:
#!/usr/bin/env perl;
use strict;
use warnings;
use Text::CSV_XS;
my ($prev_lc);
open my $fh, '<', shift or die;
my $csv = Text::CSV_XS->new({ eol => "\n" }) or die;
while ( my $row = $csv->getline($fh) ) {
if ( $csv->record_number == 1 ) {
$prev_lc = $row->[$#$row];
$csv->print( \*STDOUT, [ #$row[0 .. $#$row - 1], 'Filename' ] );
next;
}
$prev_lc =~ s/\.csv$//;
$csv->print( \*STDOUT, [ #$row[0 .. $#$row - 1], $prev_lc ] );
## Previous last column.
$prev_lc = $row->[$#$row];
}
It uses an auxiliar variable to add the missing header and process each whole data line at the same time. I simply use a regular expression to remove the extension.
With following dummy test data (infile) and assuming that last line doesn't have a file name because of the header:
mass,intensity,20130730_p12_A2.csv
2349.345,56.23423,20130730_p12_A2.csv
744.2884,5.01
Run the script like:
perl script.pl infile
That yields:
mass,intensity,Filename
2349.345,56.23423,20130730_p12_A2
744.2884,20130730_p12_A2
Perhaps it's not perfect based in particular data that you didn't show, and I didn't take into account all that code that you posted where you handle many files. But you can see that it works in the way you asked it and it's left as work for you to adapt it to your needs, if neccesary.