> > This may work for you:
> >
> > #!/usr/bin/perl
> > use warnings;
> > use strict;
> > use Fcntl ':seek';
> >
> > @ARGV = 'somefile.csv';
> > $^I = '.back';
> >
> > my @headers = map 1, split /,/, <>, -1;
> > my @keep = ( undef ) x @headers;
> >
> > while ( <> ) {
> > chomp;
> > my @fields = split /,/, $_, -1;
> > for my $i ( 0 .. $#fields ) {
> > $keep[ $i ] = $i if $fields[ $i ] ne '0.0e0';
> > }
> > last if @headers == grep defined, @keep;
> >
>
> That would probably be more efficient as:
>
> exit 0 if @headers == grep defined, @keep;
>
>
>
>
> > }
> >
> > @keep = grep defined, @keep;
> >
> > seek ARGV, 0, SEEK_SET or die "Cannot seek on '$ARGV' $!";
> >
> > while ( <> ) {
> > chomp;
> > print join( ',', ( split /,/, $_, -1 )[ @keep ] ), "\n";
> > }
> >
> > __END__
> >
I tried the original code above and received the following error:
seek() on closed filehandle ARGV at filename.pl line 24, <> line 52.
Cannot seek osn 'filename2.csv' Bad file descriptor at filename.pl
line 24, <> line 52
Since the file has 32 lines I was confused by the reference to 'line
52', so I deleted the empty line below _END_ and then repeated the
command:
perl filename.pl
Nothing happened except that the cursor in the command terminal moved
to the next line and remained, flashing without the [...] prefix. I
pressed crtl c and looked at the file using mc. The result was that my
csv file was totally emptied of content, i.e. became an empty file.
So I went to search for the text::csv module. I tried to check if this
was installed, with the resulting command terminal output:
perl -MText::CSV e -1
Can't open perl script "e": No such file or directory
$ perl -e "print qq(@INC)"
/usr/lib/perl5/5.8.8/i386-linux /usr/lib/perl5/5.8.8
/usr/lib/perl5/site_perl/5.8.8/i386-linux
/usr/lib/perl5/site_perl/5.8.8 /usr/lib/perl5/site_perl
/usr/lib/perl5/vendor_perl/5.8.8/i386-linux
/usr/lib/perl5/vendor_perl/5.8.8 /usr/lib/perl5/vendor_perl .
$ perl -MText::CSV_XS e -1
Can't open perl script "e": No such file or directory
So now I have no idea how to even check whether the module is already installed.
Next I tried to see if there is any documentation: below is my command
terminal output:
ls /usr/share/doc/perl
perl-AppConfig/ perl-IO-Socket-INET6/
perl-Archive-Cpio/ perl-IO-Socket-SSL/
perl-Archive-Tar/ perl-IO-Tty/
perl-Authen-SASL/ perl-IO-Zlib/
perl-Cairo/ perl-IP-Country-2.23/
perl-CGI-3.29/ perl-Libconf/
perl-Class-Singleton/ perl-libwww-perl/
perl-Compress-Raw-Zlib/ perl-Locale-gettext/
perl-Compress-Zlib/ perl-Mail-SPF/
perl-Config-IniFiles/ perl-Mail-SPF-Query/
perl-Crypt-SSLeay/ perl-MailTools/
perl-Curses/ perl-MDK-Common/
perl-Curses-UI/ perl-MDV-Distribconf/
perl-DateTime/ perl-MDV-Packdrakeng/
perl-DateTime-Locale/ perl-MIME-Lite/
perl-DateTime-TimeZone/ perl-Net-CIDR-Lite/
perl-DBD-mysql/ perl-Net-DBus/
perl-DB_File/ perl-Net-DNS/
perl-DBI/ perl-Net-Ident/
perl-Digest-HMAC/ perl-Net-IP/
perl-Digest-SHA1-2.11/ perl-Net-Jabber-2.0/
perl-Encode-Detect/ perl-Net_SSLeay.pm/
perl-Error/ perl-Net-Telnet/
perl-Expect/ perl-Net-XMPP/
perl-File-BaseDir/ perl-Params-Validate/
perl-File-DesktopEntry/ perl-RPM4/
perl-File-FnMatch-0.02/ perl-SOAP-Lite/
perl-File-MimeInfo/ perl-Socket6/
perl-Glib/ perl-String-CRC32/
perl-Gnome2-Print/ perl-String-ShellQuote/
perl-Gnome2-Vte/ perl-SVN/
perl-Gtk2/ perl-Sys-Hostname-Long/
perl-Gtk2-Html2/ perl-Term-ReadKey/
perl-Gtk2-NotificationBubble/ perl-TimeDate/
perl-Gtk2-SourceView-1.000/ perl-URI/
perl-Gtk2-TrayIcon/ perl-URPM/
perl-HTML-Parser/ perl-version/
perl-HTML-Tagset/ perl-XML-Parser/
perl-IO-Compress-Base/ perl-XML-Stream-1.22/
perl-IO-Compress-Zlib/ perl-Youri-Package-RPM-Updater/
No idea what this all means! I thought I would try and learn word by
word, so trying to find out what 'fcntl' means; no idea where to
start???
Totally bewildered!
Yours,
>
>
> John
> --
> Perl isn't a toolbox, but a small machine shop where you
> can special-order certain sorts of tools at low cost and
> in short order. -- Larry Wall
>
> --
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> http://learn.perl.org/
>
>
>
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