Whenever I work with CSV, I use the AnyData
module. It may add a bit of overhead, but it keeps me from making mistakes ("Oh crap, that date column is quoted and has commas in it!?").
The process for you would look something like this:
use AnyData;
my @columns = qw/date type1 type2 type3/; ## Define your input columns.
my $input = adTie( CSV , input_file.csv , r , {col_names => join( , , @columns)} );
push @columns, total ; ## Add the total columns.
my $output = adTie( CSV , output_file.csv , o , {col_names => join( , , @columns)} );
my %totals;
while ( my $row = each %$input ) {
next if ($. == 1); ## Skip the header row. AnyData will add it to the output.
my $sum = 0;
foreach my $col (@columns[1..3]) {
$totals{$col} += $row->{$col};
$sum += $row->{$col};
}
$totals{total} += $sum;
$row->{total} = $sum;
$output->{$row->{date}} = $row;
}
$output->{Total} = \%totals;
print adDump( $output ); ## Prints a little table to see the data. Not required.
undef $input; ## Close the file.
undef $output;
Input:
date,type1,type2,type3
2009-07-01,1,2,3
2009-07-03,31,32,33
2009-07-06,61,62,63
"Dec 31, 1969",81,82,83
Output:
date,type1,type2,type3,total
2009-07-01,1,2,3,6
2009-07-03,31,32,33,96
2009-07-06,61,62,63,186
"Dec 31, 1969",81,82,83,246
Total,174,178,182,534