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Re^4: Read CSV with column mapping

by coretele (Novice)
on Dec 16, 2018 at 02:11 UTC ( #1227308=note: print w/replies, xml ) Need Help??


in reply to Re^3: Read CSV with column mapping
in thread Read CSV with column mapping

I have tried adding if conditions as shown in following code but it is not skipping to add comment line and empty line. Am I doing something wrong?

while(my $colref = $csv->getline ($csv_fh)) { if (scalar(@$colref) =~ /^#/) { last; } if (scalar(@$colref) =~ /^s+$/) { last; } $output_hash{shift @{$colref}} = $colref; }
config file
#ksjlasjda abc xyz,10 xyz pqr,2 pqr stq,0.1

Replies are listed 'Best First'.
Re^5: Read CSV with column mapping
by huck (Parson) on Dec 16, 2018 at 06:15 UTC

    scalar(@$colref) is the number of items found in the column, it would never contain a '#' symbol.

    $colref->[0] is the first item on the line read in, it could contain a # symbol.

    if ($colref->[0] =~ /^#/) { next; }

    Notice i said next rather than last. next will go on to the next row, last will end the do loop and stop reading any more lines.

    the next condition is a touch more tricky.

    my $anynonblank=0; for my $item (@$colref){ unless ($item =~ /^\s+$/) { $anynonblank=1; last; } } unless ($anynonblank) { next; }
    See we have to test all of the items in this case. Note th use of last here, as soon as we have found any nonblank we dont have to check anymore.

    edit: opps , fixed as per Re^6: Read CSV with column mapping below

      unless ($item =~ /^s+$/) { ... }

      The  $item =~ /^s+$/ expression matches against a  's' literal character and not, as I think was intended, the  \s whitespace character class.


      Give a man a fish:  <%-{-{-{-<

      I have tried your suggestion and it did help to avoid comments but not for blank lines. Here I am provide the code and config file. Also providing output.

      use strict; use warnings; use Data::Dumper; use Text::CSV_XS; use IO::File; my $hash_ref = csv_file_hashref('parameters.conf'); foreach my $key (sort keys %{$hash_ref}){ print qq{$key:}; print join q{,}, @{$hash_ref->{$key}}; print qq{\n}; } sub csv_file_hashref { my ($filename) = @_; my $csv_fh = IO::File->new($filename, 'r'); my $csv = Text::CSV_XS->new (); my %output_hash; while(my $colref = $csv->getline ($csv_fh)) { if ($colref->[0] =~ /^#/) { next; } my $anynonblank=0; for my $item (@$colref){ unless ($item =~ /^\s+$/) { $anynonblank=1; last; } } unless ($anynonblank) { next; } #print @$colref; #print "\n"; $output_hash{shift @{$colref}} = $colref; } return \%output_hash; } 1;
      config file-
      #sdadwlasda abc xyz,10 #ldfgld xyz pqr,2 #jwej pqr stq,0.1 # # # #
      Output-
      : abc xyz:10 pqr stq:0.1 xyz pqr:2

        Two alternatives:

        use 5.14.1; use warnings; use Data::Peek; use Text::CSV_XS "csv"; my %hash; csv (in => "pm1227312.csv", out => undef, on_in => sub { my ($key, $value) = @{$_[1]}; $key && $key !~ m/^\s*(?:#|$)/ and $hash{$key} = $value; }); DDumper \%hash; %hash = map { @$_ } @{csv (in => "pm1227312.csv", filter => { 0 => sub + { !m/^\s*(?:#|$)/ }})}; DDumper \%hash;

        Enjoy, Have FUN! H.Merijn

        You could just check if the key is blank

        #!/usr/bin/perl use strict; use warnings; use Data::Dumper; use Text::CSV_XS; use IO::File; my $hash_ref = csv_file_hashref('parameters.conf'); foreach my $key (sort keys %$hash_ref){ print $key.':'; print join ',', @{$hash_ref->{$key}}; print "\n"; } sub csv_file_hashref { my ($filename) = @_; my %output_hash = (); my $csv_fh = IO::File->new($filename, 'r'); my $csv = Text::CSV_XS->new( { allow_whitespace => 1 } ); while (my $row = $csv->getline($csv_fh)){ my $key = shift @$row; next if $key =~ /^#/; if ($key =~ /\S/){ $output_hash{$key} = $row ; } } return \%output_hash; }

        Note $item =~ /^\s+$/ matches 1 or more white space only (but not nothing). Try $item =~ /^\s*$/ in your code.

        poj

        /^\s+$/ requires at least one blank character. /^\s*$/ would fail empty lines too.

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