如何使用perl在csv文件中插入空列

Question

I have a list of CSV file i need to add number of empty column on each, the number of empty column i need to add change on each file in a linear way, first file i want to insert 0 column, second file i want to insert 1 column, third file i want to insert 2 column and so on, the column should be inserted always as second one. all the input file are a 2 column csv as the example below

file 1

2016/03/07 23:42:40.618 GMT,54.5
2016/03/07 23:43:40.618 GMT,54.0771
2016/03/07 23:44:40.618 GMT,53.9472
2016/03/07 23:45:40.618 GMT,54.2914

file 2

2016/03/07 23:42:40.618 GMT,49.013
2016/03/07 23:43:40.618 GMT,48.688
2016/03/07 23:44:40.618 GMT,47.7052 
2016/03/07 23:45:40.618 GMT,47.9057

file3

2016/03/07 23:51:40.618 GMT,50.7858
2016/03/07 23:52:40.618 GMT,52.5267
2016/03/07 23:53:40.618 GMT,54.2865
2016/03/07 23:54:40.618 GMT,53.2014
2016/03/07 23:55:40.618 GMT,52.0538

etc.

I want the output to be

file1

2016/03/07 23:42:40.618 GMT,54.5
2016/03/07 23:43:40.618 GMT,54.0771
2016/03/07 23:44:40.618 GMT,53.9472
2016/03/07 23:45:40.618 GMT,54.2914

File2

2016/03/07 23:42:40.618 GMT,,49.013
2016/03/07 23:43:40.618 GMT,,48.6883
2016/03/07 23:44:40.618 GMT,,47.7052
2016/03/07 23:45:40.618 GMT,,47.9057

file3

2016/03/07 23:51:40.618 GMT,,,50.7858
2016/03/07 23:52:40.618 GMT,,,52.5267
2016/03/07 23:53:40.618 GMT,,,54.2865
2016/03/07 23:54:40.618 GMT,,,53.2014
2016/03/07 23:55:40.618 GMT,,,52.0538

This is the code wrote but it generate the same output for all file with added just one empty column, probably i'm missing something silly but i can't get what

#!/usr/bin/perl
#use strict; 
#use diagnostics;
use CGI qw(:standard);
use Cwd;
use File::Find;
use File::Basename;
use Text::CSV;
use Text::Trim qw(trim);
use List::MoreUtils qw(uniq);
use Text::CSV_XS;
sub read_dir{
    my $ph=$_[0];
    my $match=$_[1];
    my @fl = ( );
    #print "<b> will open $ph";
    opendir DH, "$ph" or die "Cannot open Dir $ph: $!";
    #if ($match eq "") {
    @fl = grep !/^\.\.?$\.*/, sort(readdir DH) ;
    #}
    #else {
    #   my @fl = grep {$_ =~ $match} sort(readdir DH) ;
    #}
    closedir DH;
    if ($match ne "") {
        foreach my $file (@fl){
            if ($file =~$match) {
                push(@ffl,$file);
            }
        }
        return @ffl;
    }
    else {
        return @fl;
    }
}
@column=();
$loc="/myfolder";
$offset=1;
@sites=("dir1","dir2","dir3");
$s="subdir";
foreach $t (@sites) {
    $m=0; #number of empty column to insert in the file
    @list=read_dir("$loc/Statistics/$t/$s"); #directory that contain the csv file to manipulate
    foreach $l (@list) {
        #inser the empty column 
        open $in, "<","$loc/Statistics/$t/$s/$l" or die $!;
        open $out, ">>", "$loc/Statistics/$t/$s/$l.tmp" or die $!;
        foreach $r (0..$m) {
            print "<br> r is $r";
            open $out, ">>", "$loc/Statistics/$t/$s/$l.tmp" or die $!;
            while ($row = $ccsv->getline($in)) {
                splice @$row, $offset, 0, shift @column;
                $ccsv->print($out, $row);
            }
            close $out;
        }
        close $in;
        $m=$m+1;
    }
}

Answer 1

perl -i~ -pe '
    s/,/"," x (1 + $commas)/e;
    $commas++ if eof;
' -- file1 file2 file3

• -p reads the file line by line, after running the code, it prints it
• -i~ changes the input files "in place", saving a backup as file1~ etc.
• s/,/"," x $commas/e substitutes a comma with evaluated code in the replacement part, ie the comma repeated one time for the first file, two times for the second, and so on
• eof returns true every time an input file ends, see eof
• $commas++ adds 1 to $commas