使用Perl在列中读取具有多个值的csv文件

Question

I want to delete a column from csv file using perl, for that I am splitting the line on ",", but there are some columns with multiple values and hence multiple commas. That is each line may have different number of commas, so its hard to delete a column that I want to be deleted. Can you help in doing so?

Answer 1

For processing CSV files, use an actual csv parser like Text::CSV .

This will take care of the instances of fields enclosed in quotes because they contain commas.

Answer 2

Suppose your file looks like

Tudor,Vidor,10,Hapci
Szundi,Morgo,7,Szende
Kuka,"Hofeherke, alma",100,Kiralyno
Boszorkany,Herceg,9,Meselo

and you want to find sum of 3rd column, but in 3rd row you see the 2nd column has value with comma so to handle that use Text::CSV as:

#!/usr/bin/perl
use strict;
use warnings;

use Text::CSV;
my $csv = Text::CSV->new({ sep_char => ',' });

my $file = $ARGV[0] or die "Need to get CSV file on the command line\n";

my $sum = 0;
open(my $data, '<', $file) or die "Could not open '$file' $!\n";
while (my $line = <$data>) {
  chomp $line;

  if ($csv->parse($line)) {

      my @fields = $csv->fields();
      $sum += $fields[2];

  } else {
      warn "Line could not be parsed: $line\n";
  }
}
print "$sum\n";

If you'd prefer to access the fields in your CSV file by name, use Tie:Handle::CSV