1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Parsing CSV File Using Perl

Discussion in 'Perl' started by pradeep, Jun 6, 2008.

  1. pradeep

    pradeep Team Leader

    Apr 4, 2005
    Likes Received:
    Trophy Points:
    Kolkata, India
    Home Page:


    CSV is a comma separated value data file is a physical ASCII file structure that contains records whose values are delimited or separated by commas. CSV is a common file type which can be imported into spreadsheet applications such as MS-Excel, database applications such as MS-Access, and contact databases such as MS-Outlook, ACT, Goldmine, etc. The format dates back to the early days of business computing. For this reason, CSV files are common on all computer platforms.

    CSV is one implementation of a delimited text file, which uses a comma to separate values (where many implementations of CSV import/export tools allow an alternate separator to be used; as is shown in the MS Access screen shot, below). However CSV differs from other delimiter separated file formats in using a " (double quote) character around fields that contain reserved characters (such as commas or newlines). Most other delimiter formats either use an escape character such as a backslash, or have no support for reserved characters.

    In some application you might need to allow user to upload a CSV data file, which is processed and inserted to the DB, thereby avoiding the direct interaction of the user with the DB, the user can prepare his/her report/data in MS Excel, or a similar spreadsheet program which can be later uploaded using a web interface.

    Parsing The CSV File Programatically

    The simplest solution would be to read the uploaded file line-by-line and splitting the lines by commas, but this is not fool proof, just in case the one of the fields contain a comma which is not a delimiter but a part of the data, then your code goes for a toss. So, we we'll use the popular CSV parsing module, Text::CSV to get the work done for us.

     $csv = Text::CSV->new();              # create a new object
     $status  = $csv->parse($line);        # parse a CSV string into fields
     @columns = $csv->fields();            # get the parsed fields
    The above code snippet shows the basic usage of this module. You can get more info here http://search.cpan.org/~makamaka/Text-CSV-1.05/lib/Text/CSV.pm

    A Complete Upload and Parsing Script

    This script receives a CSV file via file upload, and parses the CSV file and display them in a HTML table. Hope this is helpful to you.

     ## parsing a CSV file uploaded using a web interface, using Text::CSV
     use strict;
     use CGI;
     use CGI::Carp qw/fatalsToBrowser warningsToBrowser/;
     use Text::CSV;
     use Data::Dumper;
     my $csv = Text::CSV->new(); ## pass parameter {binary=>1} if you want to handle non-ascii chars
     my $cgi = new CGI;
     if($ENV{'REQUEST_METHOD'} eq 'POST')
         print $cgi->header();
         my $h = $cgi->upload('up');
         my $total_rows = 0;
         print "<table border=1>";
         while(my $line = <$h>)
                 print q(<tr>);
                 print qq(<td>$_</td>) for($csv->fields());
                 print q(</tr>);
         print "</table>";
         print $cgi->header(),qq(<html><head><title>CSV Upload Parser</title>
             <form method="POST" enctype="multipart/form-data">
             <input type="file" name="up"><br><br>
             <input type="submit" name="bt" value="Upload">

Share This Page