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# 1  
Old 01-08-2011
Read column into hash
Hi, I want to read the __DATA__ into hashes with the first word (indented) of each part as key and the rest of the part (an array as value). Each part of the input is identified by the indentation. i.e. "The Skipper", "Professor", "Gilligan" are three identifiers as they do not have indentation, but the rest are indented in my original data (Here I used "_" instead because of the display in the forum post). The out put should be like:
Code:
The Skipper => blue_shirt  hat  jacket  preserver  sunscreen
Professor    => sunscreen  water_bottle  slide_rule
Gilligan       =>  red_shirt  hat  lucky_socks  water_bottle

The code pushes all of the data into a single hash entry, not three. Can anybody give me some help on this?

Thanks a lot!

Yifangt
Code:
#!/usr/bin/perl -w
use strict;
use Data::Dumper;

my %provisions;
my @person;
my @hash_array;

while (<DATA>) {
    if (/^\S.*/) {                 # a person's name (no leading whitespace)
        push @person, $1;
        push @hash_array, $provisions{$person[$#person]};
    } elsif (/^\s+(\w.*)/) {         # word started with indentation as array member as hash value
          push @{$provisions{$person[$#person]}}, $1;  # push the word into array
               } else {
        die "I don't understand: $_";
          }
}
print Dumper %provisions, "\n";

__DATA__
The Skipper
 _blue_shirt
 _hat
 _jacket
 _preserver
 _sunscreen
Professor
 _sunscreen
 _water_bottle
 _slide_rule
Gilligan
 _red_shirt
 _hat
 _lucky_socks
 _water_bottle

The output is:
Code:
$VAR1 = '';
$VAR2 = [
          'blue_shirt',
          'hat',
          'jacket',
          'preserver',
          'sunscreen',
          'sunscreen',
          'water_bottle',
          'slide_rule',
          'red_shirt',
          'hat',
          'lucky_socks',
          'water_bottle'
        ];
$VAR3 = '
';

Last edited by Scott; 01-09-2011 at 03:25 AM.. Reason: Code tags, please...
# 2  
Old 01-08-2011
In:
Quote:
Originally Posted by yifangt
Code:
    if (/^\S.*/) {                 # a person's name (no leading whitespace)
        push @person, $1;
        push @hash_array, $provisions{$person[$#person]};
    }

The hash, $provisions{$person[$#person]} is not defined, so nothing is being pushed onto @hash_array. You need to initialize, with:
Code:
push @hash_array, $provisions{$person[$#person]} = {};

Last edited by m.d.ludwig; 01-08-2011 at 07:01 PM.. Reason: bad editing
# 3  
Old 01-08-2011
reply: Read columns into hash
Thanks ludwig!

Although I thought I defined the hash at the beginning, it seems you got the points: after I changed into your code, the problem is related to this. But it did not work still!
===================Erro message =================
Global symbol "%provisions" requires explicit package name in program.pl" which is the error message from my console.
======================================
Strange! Could not figure out the bug.
More clue?

Thanks again! yifangt
# 4  
Old 01-08-2011
My apologies, it should have [], not {}. But to simplify the inner workings of the while loop:
Code:
  if (/^(\S.*)$/) { # a person's name (no leading whitespace)
    push @person, $1;
    push @hash_array, $provisions{$person[-1]} = [];
    next;
  }

  if (/^\s+(\w.*)/) { # word started with indentation as array member as hash value
    push @{$provisions{$person[-1]}}, $1; # push the word into array
    next;
  }

  die "I don't understand: $_";

In case you are wondering, $person[-1] is also the last element of a list.
# 5  
Old 01-08-2011
reply: Read columns into hash!
Thanks a lot!

First, thank you for the regex line for the person's name. That makes much more sense.

Second, what I was thinking is: each time only one item was pushed into the array, why need the anonymous array []?

I am aware of this case is twisty, and need to digest it a little bit more.

Thank you again!

Yifangt
# 6  
Old 01-08-2011
Were you invoking the script as perl scriptname or ./scriptname??
# 7  
Old 01-08-2011
reply: Read columns into hash!
The first one "perl scriptname".
Does that matter to the result?

The script is working anyway. I modified the code a little bit for the output. Everything is fine now.

Thanks a lot!

Yifangt
Code:
#!/usr/bin/perl -w
use strict;
use Data::Dumper;

my %provisions;
my @person;
my @hash_array;

while (<DATA>) {
    if (/^(\S.*)$/) {         # a person's name (no leading whitespace)
    push @person, $1;
    push @hash_array, $provisions{$person[-1]} = [];
    next;
  }

  if (/^\s+(\w.*)/) { # word started with indentation as array member as hash value
    push @{$provisions{$person[-1]}}, $1; # push the word into array
    next;
  }

  die "I don't understand: $_";
}
#print Dumper @person, "\n";
#print Dumper @hash_array, "\n";
#print Dumper %provisions, "\n";

foreach my $key (keys %provisions) {
    print $key, "\t=>\t", "@{$provisions{$key}}", "\n";
    }

==========Output=======perl program_script.pl======
Code:
Professon    =>    sunscreen water_bottle slide_rule
The Skipper    =>    blue_shirt hat jacket preserver sunscreen
Gilligan    =>    red_shirt hat lucky_socks water_bottle

Last edited by Scott; 01-09-2011 at 03:26 AM.. Reason: Code tags, please...
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