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Hash or hash's of hash?

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Hello,

I am a beginner in Perl. I am trying to read and then process a pipe delimited file. My file looks something like this-

size|3
directory|c:\un icorn
sub-directories|sub |new.....

The examples I have seen online show code where it is known how many columns the file consists. However, this is going to be a configuration file and number of columns in sub-directories is unknown.

My question is what do I need has or hash's of hash or something else in this case?

Thanks!
Jun 29 '12 #1
3 1735
RonB
589 Recognized Expert Moderator Contributor
You can use a hash, or a hash of arrays, or a hash of hashes. You haven't provided enough info for use to be able to make a clear recommendation.

Is the file format set in stone i.e., is it being dictated by your instructor/boss? If you can, I'd recommend changing it to a more standard config file format and possibly use one of the config modules on cpan to parse it.
Jun 29 '12 #2
RonB
589 Recognized Expert Moderator Contributor
Here's one option.

Expand|Select|Wrap|Line Numbers
  1. #!/usr/bin/env perl
  2.  
  3. use strict;
  4. use warnings;
  5. use Data::Dumper;
  6.  
  7. my %cfg;
  8.  
  9. while (my $line = <DATA>) {
  10.     chomp $line;
  11.     my ($key, @values) = split /\|/, $line;
  12.  
  13.     if (@values > 1) {
  14.         $cfg{$key} = \@values;
  15.     }
  16.     else {
  17.         $cfg{$key} = $values[0];
  18.     }
  19. }
  20. print Dumper \%cfg;
  21.  
  22. __DATA__
  23. size|3
  24. directory|c:\unicorn
  25. sub-directories|sub|new
which outputs:
Expand|Select|Wrap|Line Numbers
  1. $VAR1 = {
  2.           'sub-directories' => [
  3.                                  'sub',
  4.                                  'new'
  5.                                ],
  6.           'directory' => 'c:\\unicorn',
  7.           'size' => '3'
  8.         };
  9.  
Jun 29 '12 #3
numberwhun
3,509 Recognized Expert Moderator Specialist
If I may add to this, take a look at this link. I have used it as a reference for hashes in Perl and it has been extremely handy. Hopefully it helps.

Regards,

Jeff
Jul 2 '12 #4

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