Re^6: Undef values from file open

[Anonymous Monk]

Here, and I can not get it to work:

#!/usr/bin/perl

use strict;
use warnings;

use Data::Dump 'pp';
use Data::Dumper;

my $file_name = "file.csv";

open my $lines, '<', $file_name
  or die "Can't open file $file_name, $!";

my @parms = qw( date day name );

while (my $line = <$lines>) {

    next unless $line =~ /\S/;  # <- add

   chomp $line;
   
   my $data;

   
   ( $data->{ date }, $data->{ day }, $data->{ name } ) = split(/,/, $
+line);
   
   pp @{ $data }{ (@parms) };
}

[poj]

What do you get with this

#!/usr/bin/perl
use strict;
use warnings;
use Data::Dump 'pp';

my $file_name = "file.csv";
open my $lines, '<', $file_name
  or die "Can't open file $file_name, $!";

while (my $line = <$lines>) {
  pp $line;
}

[Anonymous Monk]

It prints all the data from the file no problem, this line also prints:

print "$data->{ date }, $data->{ day }, $data->{ name }\n"

This one gets me nothing:

 pp @{ $data }{ (@parms) };

[AnomalousMonk]

Here's another step along the debugging path poj began here. We know that each line of the file is being read correctly; now, what happens when we process a line and assign its sub-strings to the  $data hashref?

c:\@Work\Perl\monks\Anonymous Monk\1158543>perl -e
"use strict;
 use warnings;
 use Data::Dump 'pp';
 ;;
 my $file_name = 'file.csv';
 open my $lines, '<', $file_name
   or die qq{opening file '$file_name': $!};
 ;;
 while (my $line = <$lines>) {
   pp $line;
   next unless $line =~ /\S/;
   chomp $line;
   my $data;
   ($data->{date}, $data->{day}, $data->{name}) = split(/,/, $line);
   pp $data;
   print qq{------- \n}
   }
"
"01/04/2014,Friday,Joe\n"
{ date => "01/04/2014", day => "Friday", name => "Joe" }
-------
"02/11/2011,Monday,Mary\n"
{ date => "02/11/2011", day => "Monday", name => "Mary" }
-------
"05/09/2016,Monday,Ann\n"
{ date => "05/09/2016", day => "Monday", name => "Ann" }
-------
"07/02/2013,MOnday,Marc\n"
{ date => "07/02/2013", day => "MOnday", name => "Marc" }
-------
"\n"

What do you get when you run this code? Note that my data file contains a blank line at the end for which no further processing is done, as expected, so this aspect of the program works.

BTW: I'd still be curious to know the exact version of Perl you're using. I don't really know what being "current" means.

[poj]

What does pp $data give, and what version of perl do you have ?

[poj]

What does pp @parms; give you ?

[Anonymous Monk]

My Perl version is current, I get undef for all values.

[AnomalousMonk]

Here's what I get from the code you just posted and the data from above:

c:\@Work\Perl\monks\Anonymous Monk\1158543>perl -e
"use strict;
 use warnings;
 ;;
 use Data::Dump 'pp';
 use Data::Dumper;
 ;;
 my $file_name = \"file.csv\";
 ;;
 open my $lines, '<', $file_name
   or die \"Can't open file $file_name, $!\";
 ;;
 my @parms = qw( date day name );
 ;;
 while (my $line = <$lines>) {
   next unless $line =~ /\S/;
   chomp $line;
   my $data;
   ( $data->{ date }, $data->{ day }, $data->{ name } ) = split(/,/, $
+line);
   pp @{ $data }{ (@parms) };
  }
"
("01/04/2014", "Friday", "Joe")
("02/11/2011", "Monday", "Mary")
("05/09/2016", "Monday", "Ann")
("07/02/2013", "MOnday", "Marc")

[Anonymous Monk]

It's a mystery to me, why this line:

print "$data->{ date }, $data->{ day }, $data->{ name }\n"

prints all the values and this one gets me undefs:

 pp @{ $data }{ (@parms) };

I'm stuck on this one!

[Anonymous Monk]

And this line prints anything for you?

pp @{ $data }{ (@parms) };

[AnomalousMonk]

It prints what I posted:

("01/04/2014", "Friday", "Joe")
...
("07/02/2013", "MOnday", "Marc")

What I posted was a line-by-line screenshot (a lineshot?) (update: aka a cut-and-paste) of my Windows command line interpreter window for your program and its output.