From: "Mihir Kamdar" <[EMAIL PROTECTED]>
> I have a csv file. I wanted to do some calculations on some of its fields,
> like multiplying the 7th field with the 13th field and overwriting the 13th
> field with the answer of my calculation.
>
> Regarding this, can I do the calculations on the input file and overwrite it
> after calculating, or I will have to open the output file and write into it?
> I am asking this because I will have several files in the directory. So, I
> will have to read the directory using readdir, and process each file. It is
> better if I open the file in read-write mode, process it and overwrite the
> file. Just wanted to know if it is safe?
I think you should use either DBD::CSV or DBD::AnyData and SQL to
make your changes.
Something like
#!/usr/bin/perl
use strict;
use DBI;
my $dbh = DBI->connect("DBI:CSV:f_dir=/dir/with/the/csvs")
or die "Cannot connect: " . $DBI::errstr;
$dbh->{'csv_tables'}->{'SomeName'} = { 'file' =>
'SomeName20070827.csv'};
# tie the table name to the filename
my $sth = $dbh->prepare('UPDATE SomeName SET Foo = Foo * Bar');
$sth->execute();
# specify an execute the action
__END__
And that's it. Let the modules do the heavy work for you.
Jenda
P.S.: If you do not know SQL, learn it! You can be a productive
programmer without knowing anything about XML or whatever's the
current hype, you can't be one without SQL.
===== [EMAIL PROTECTED] === http://Jenda.Krynicky.cz =====
When it comes to wine, women and song, wizards are allowed
to get drunk and croon as much as they like.
-- Terry Pratchett in Sourcery
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