How to get out an array of a hash?

buchi2 has asked for the wisdom of the Perl Monks concerning the following question:

Hello!

In article 1195995 I got it work with your help to build an array of hashes.
Now I want to get out a whole array of it, but it is always empty.

#!/usr/bin/perl -w

use strict;
use warnings;

my %hierhash;
my @feld;
my @hashfeld;
my $wert;
my @array;

@hashfeld = ();

%hierhash = &dofn(0,5,1);
print "1 $hierhash{'var2'}[3] \n";

push @hashfeld, {%hierhash};

%hierhash = &dofn(0,5,2);
print "2 $hierhash{'var2'}[3] \n";
push @hashfeld, {%hierhash};

$wert = $hashfeld[0]->{'var2'}[3]; 
print "$wert\n";
$wert = $hashfeld[1]->{'var2'}[3]; 
print "$wert\n";
@array = ();
@array = $hashfeld[1]->{'var2'};
print "array $array[3]\n";

# ################################################
# holt die fn Werte
# ################################################
sub dofn  {
   my $i;
   my ($ivon, $ibis, $imal) = @_;
   my %hashfn;

   for ($i = $ivon; $i < $ibis; $i++) {
      push @{$hashfn{'var1'}}, $i*$imal;
      push @{$hashfn{'var2'}}, $i*$imal*10.;
      push @{$hashfn{'var3'}}, $i*$imal*20.;
   }

   return %hashfn;
}
[download]

What is going wrong with it?

Regards, Buchi

Comment on How to get out an array of a hash? Download Code

Replies are listed 'Best First'.
Re: How to get out an array of a hash? by shmem (Chancellor) on Aug 03, 2017 at 09:02 UTC
Now it's time to read References quick reference. perl -le'print map{pack c,($-++?1:13)+ord}split//,ESEL'	[reply]
Re: How to get out an array of a hash? (Updated) by thanos1983 (Parson) on Aug 03, 2017 at 08:21 UTC
Hello buchi2, You are getting an array of arrays, I have altered the output so you can see it easier. Read more... (1519 Bytes) From there it is easy (I guess) on how to get the array or at least you can search online on how to extract an array from an array of arrays ;) A few minor recommendations regarding your code (very briefly). You do not need to add the `-w` on the shebang, `-w` it is an alternative of using `use warnings;`. Also you do not need to use the `&` on your subroutines see here why What is the point of the & / ampersand sigil for function refs?. Update: I used Data::Dumper to debug the output, I think you will find it extremely useful, at least I do. :) Update2: Fellow monk hexcoder provided you already an answer to your question so I thought it would be nice also to add some minor notes on your code. In Perl you do not need to predefine your variables you can define them the moment you assign them. Also I found very useful the feature say. It is like print but it add an new line character `\n` at the end your string or what ever attribute you are calling. Read more... (1369 Bytes) Update3: One more reference to read from a similar question Dereference array of arrays. Hope this helps, BR. Seeking for Perl wisdom...on the process of learning...not there...yet!	[reply] [d/l] [select]
Re: How to get out an array of a hash? by hexcoder (Curate) on Aug 03, 2017 at 08:25 UTC
Hi, you need to change the access to an array reference `$hashfeld[1]->{'var2'}`. Dereference it in order to get the referenced values . `@array = $hashfeld[1]->{'var2'};` [download] => `@array = @{$hashfeld[1]->{'var2'}};` [download]	[reply] [d/l] [select]
Re: How to get out an array of a hash? by Anonymous Monk on Aug 03, 2017 at 09:20 UTC
In `sub dofn {` you write 'var1', 'var2', 'var3' 'var1', 'var2', 'var3' is spelled @array `my @fn; push @{ $fn[1] }, 1.11; push @{ $fn[2] }, 2.1; push @{ $fn[3] }, 3.1; Data::Dump::dd(\@f);` [download]	[reply] [d/l] [select]