http://www.perlmonks.org?node_id=996991


in reply to Re: Processing CSV File
in thread Processing CSV File

Thanks for the response.. I did the following;

#!/usr/bin/perl # $template_file_name="rtr-template.txt"; open(OFILE, "> test") || die "output config file $ofile_name: $!\n"; while(<>) { ($location, $name, $lo0ip, $frameip, $framedlci, $eth0ip, $x) = split (/,/); open(TFILE, "< $template_file_name") || die "config template file $ +template_file_name: $!\n"; $ofile_name = $name . ".txt"; while (<TFILE>) { s/##location##/$location/; s/##rtrname##/$name/; s/##eth0-ip##/$eth0ip/; s/##loop0-ip##/$lo0ip/; s/##frame-ip##/$frameip/; s/##frame-DLCI##/$framedlci/; printf OFILE $_; } }

I tried just moving the line as is, but since $ofile_name hadn't been defined yet, that would't work.. so i replaced the variable with 'Test' This creates a file called Test with the information required.. however still only processes the first line of the CSV - as i guess is expected, as it is emulating the same problem as before.. If i move the line "$ofile_name = $name . ".txt";" to the top aswell, so it looks like:

#!/usr/bin/perl # $template_file_name="rtr-template.txt"; $ofile_name = $name . ".txt"; open(OFILE, "> test") || die "output config file $ofile_name: $!\n"; while(<>) { ($location, $name, $lo0ip, $frameip, $framedlci, $eth0ip, $x) = split (/,/); open(TFILE, "< $template_file_name") || die "config template file $ +template_file_name: $!\n"; while (<TFILE>) { s/##location##/$location/; s/##rtrname##/$name/; s/##eth0-ip##/$eth0ip/; s/##loop0-ip##/$lo0ip/; s/##frame-ip##/$frameip/; s/##frame-DLCI##/$framedlci/; printf OFILE $_; } }

then when i run the code, I don't get any files outputted.. Do you have any ideas, what is going on... Thanks again

Replies are listed 'Best First'.
Re^2: Processing CSV File
by Kenosis (Priest) on Oct 03, 2012 at 07:57 UTC

    If I may suggest considering a slightly different approach to your task...

    It appears that you're opening the template file each time a csv line is read, so that you can fill in the template with the entries. Consider opening the template file only once, and grabbing its contents into a scalar. Then, you can do the substitutions on a copy of that scalar, and write that copy to a file. Doing that may look something like this:

    #!/usr/bin/perl # use strict; use warnings; my ( $templateText, %hash ); my $template_file_name = 'rtr-template.txt'; my @vars = split "\n", <<END; ##location## ##rtrname## ##loop0-ip## ##frame-ip## ##frame-DLCI## ##eth0-ip## END { local $/; open my $fh, '<', $template_file_name or die "$template_file_name: + $!"; $templateText = <$fh>; close $fh; } while (<>) { chomp; @hash{@vars} = split /,/; my $templateTextCopy = $templateText; $templateTextCopy =~ s/$_/$hash{$_}/g for keys %hash; my $ofile_name = $hash{'##rtrname##'} . '.txt'; open my $fh, '>', $ofile_name or die "$ofile_name: $!"; print $fh $templateTextCopy; close $fh; }

    You'll notice this notation: @hash{@vars} = split /,/; It pairs the elements of @var as keys with the split entries of the csv line as values of %hash. This creates the hash that's used in the substitution line, taking the place of the six substitution lines. Also, note that the substitution is global, because your script was going through all the lines of the template for the substitutions.

    Hope this helps!

      Thanks, This is a great version of the code.. One question for you.. How would I change the "my $template_file_name = 'rtr-template.txt'" line to chose a template that is specified in the CSV.. rather than a file saved on the HDD.. So if I just added another column to the CSV.. this would make the script a bit more dynamic for different templates.. Thanks!

        Hi, Perl3r.

        Try the following:

        #!/usr/bin/perl # use strict; use warnings; $ARGV[0] or die "Usage: $0 <filename> [<filename>] ..."; my ( $template_file_name, $templateText, %hash ) = ''; my @vars = split "\n", <<END; ##location## ##rtrname## ##loop0-ip## ##frame-ip## ##frame-DLCI## ##eth0-ip## END while (<>) { chomp; my @fields = split /,/; my $templateFN = pop @fields; if ( $template_file_name ne $templateFN ) { $template_file_name = $templateFN; undef $templateText; } @hash{@vars} = @fields; $templateText //= getTemplateText($template_file_name); my $templateTextCopy = $templateText; $templateTextCopy =~ s/$_/$hash{$_}/g for keys %hash; my $ofile_name = $hash{'##rtrname##'} . '.txt'; open my $fh, '>', $ofile_name or die "$ofile_name: $!"; print $fh $templateTextCopy; close $fh; } sub getTemplateText { my ($template_file_name) = @_; local $/; open my $fh, '<', $template_file_name or die "$template_file_name: + $!"; $templateText = <$fh>; close $fh; return $templateText; }

        The last CSV column needs to contain the template's file name. The script can handle multiple files at once, e.g.:

        processCSV.pl csv1.csv csv2.csv

        The script uses Perl's 'defined-or-equals' operator to only read the template's text once, and will read in a new template if it detects a change in the template's file name (e.g., when going from csv1.csv to csv2.csv).