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Re^5: edit a CSV and "in-place" replacement

by Tux (Abbot)
on Jun 22, 2012 at 09:31 UTC ( #977811=note: print w/replies, xml ) Need Help??

in reply to Re^4: edit a CSV and "in-place" replacement
in thread edit a CSV and "in-place" replacement

The original question was "in-place-editing" required. Using the CSV module(s) Text::CSV_XS (used in DBD::CSV) and/or Text::CSV (which uses Text::CSV_XS if available for speed) you cannot in-place edit, but you can set up two instances: one for input, and one for output. This has to be used instead of DBD::CSV if there are no headers or no unique keys, somewhat along these lines:

my $ci = Text::CSV_XS->new ({ binary => 1, auto_diag => 1 }); my $co = Text::CSV_XS->new ({ binary => 1, auto_diag => 1, eol => "\n" + }); open my $fi, "<:encoding(utf-8)", "google.csv"; open my $fo, ">:encoding(utf-8)", "contacts.csv"; while (my $row = $ci->getline ($ci)) { $row->[34] =~ s/^0/+91/; $co->print ($fo, $row); } close $fi; close $fo;

Which is safe for embedded comma's as you describe (when correctly quoted). On huge files, you can speed this even using bind_columns ().

Another (huge) advantage is that this is MUCH faster than using DBD::CSV, has no size limits (other than disk storage) and can be used in streams, both in and out. DBD::CSV is likely to keep the complete file in memory, probably even twice.

Enjoy, Have FUN! H.Merijn

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