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POLooping over an array to build a multidimensional array in Perl, converting from PHP, and syntactically wrong
 

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  1. POLooping over an array to build a multidimensional array in Perl, converting from PHP, and syntactically wrong
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    <p>Working on converting an array to another array. In PHP, this is easy, but Perl has some syntax that I am having a hard time getting my head around and understanding.</p> <p>Here is my loop in Perl:</p> <pre><code>foreach my $r (@toindex){ #print Dumper $r; %indexed{@$r[0]}{'image_id'} = @$r[0]; #Broken %indexed{"@$r[0]"}{'image_id'} = @$r[0]; #Broken } </code></pre> <p>Here is my @toindex array</p> <pre><code>$VAR1 = [ [ 3638584, 'Aperture', 'F13' ], [ 3638588, 'Exposure Bias', '0 EV' ], [ 3638588, 'Focal Length', '80.0 mm' ], ]; </code></pre> <p>And here is what I want to do, but in PHP</p> <pre><code>foreach($indexrows as $k =&gt; $v){ $indexed[$v['image_id']]['image_id'] = $v['image_id']; } </code></pre> <p>It seems so very simple in PHP, but moving it to Perl is proving to be quite a challenge for me.</p> <hr> <p>Update</p> <p>Thanks to the help of Sinan Ünür and DVK with that final little pointer, I have a working solution. I'm posting the complete script in case anyone might find some part of it useful in the future.</p> <pre><code>#!/usr/bin/perl use strict; use warnings; use DBI; use Data::Dumper; my $dbh = DBI-&gt;connect('dbi:Pg:dbname=database;host=serveraddress','user','password') or die; my $sth; my $sql = "SELECT id, field, data FROM table"; my $offset = 0; my $increment = 20; my $toindex; # This loop here is to solve a problem that was not part of the # original question. I included it to illustrate the syntax for # looping a database query do{ $sth = $dbh-&gt;prepare($sql . " LIMIT " . $increment . " OFFSET " . $offset); $sth-&gt;execute or die; $toindex = $sth-&gt;fetchall_arrayref; $offset = $offset + $increment; }while(@$toindex == 0); # Alternately, if you do not need a loop below is all you need # $sth = $dbh-&gt;prepare($sql); # $sth-&gt;execute or die; # $toindex = $sth-&gt;fetchall_arrayref; my %indexed; foreach my $r ( @$toindex ) { #print Dumper $r; my ($id, $field, $value) = @$r; @{ $indexed{ $id } }{('image_id', $field)} = ($id, $value); } print Dumper %indexed; $dbh-&gt;disconnect; </code></pre>
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    1. USBen Dauphinee
    1. USBen Dauphinee
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    1. COI tend to view gratuitous language comparisons very negatively. So, you do not how to do something in Perl which you do know how to do in PHP. You can simply ask *"How can I do X in Perl?"* instead of complaining about the syntax of a language whose documentation you don't seem to have read at all. See http://perldoc.perl.org/perldsc.html
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      1. POLooping over an array to build a multidimensional array in Perl, converting from PHP, and syntactically wrong
      1. USSinan Ünür
    2. CO@Sinan As I stated in the other thread, I have looked through the docs. My problem is that the examples are simple, and therefore not really helping me with debugging these issues. Having an error message like 'your syntax is wrong' is not helpful enough, and even with all the Google searches I am doing, I still cannot work this stuff out. I know how to do it in PHP because it's easy, so I stated that and provided a working example of what I want to do in the language I know.
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      1. USBen Dauphinee
    3. CO@Ben That is why you need to actually study a language a little bit, understanding the basic rules of it before you accept a job that requires you to use it.
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      1. USSinan Ünür
 

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