de-referencing @$

kevind0718 has asked for the wisdom of the Perl Monks concerning the following question:

Hello Kind and Wise Monks:

I have tried many ways to de-reference a variable. And yes I looked at http://perldoc.perl.org/perlreftut.html. Specifically where they talk about ->. I have one bit of code that works, but I know it could be simpler.

. Here is the code that works:

  for my $e (@$bbData)   {
     print Dumper $e;     
     
     my $d = $e->[0]; 
       ##print Dumper $d;  
     print "Col Zero: " . $e->[0] . "  Col One: " . $e->[1] . "  Col F
+our: " . $e->[4] . " \n" ;
       ##print "Col Zero: " . $d  . " \n" ;
   

     #foreach $tmp (@aDim) {
     #   print $tmp
     
  }
[download]

This code prints the variables as expected. I would like to eliminate the loop, because there is only one element in the outer most array.

This bit of code does not work.

      print "Error: " . Win32::OLE->LastError  . "\n";
      print Dumper $bbData;
      $e  =   $bbdata->[0];
      print Dumper $e;
      
      print $SQLUpdate  .  $SQLUpdateWhere  . "\n";
[download]

It produces the following output:

Error: 0
$VAR1 = [
          [
            'VANGUARD TELECOM SERVICE ETF',
            'B031NG6',
            '92204A884',
            'US92204A8844',
            'MSCITC'
          ]
        ];
$VAR1 = undef;
 update security set underlyingbloomberg =   where securitykey =
[download]

I do not what to use the FOR loop because there is never more than one interior array. There must be a syntax that allows me to directly access the array contained in $bbdate[0].

many thanks for your kind assistance.

kd

Comment on de-referencing @$ Select or Download Code

Replies are listed 'Best First'.
Re: de-referencing @$ by kyle (Abbot) on Sep 30, 2008 at 19:14 UTC
I say unto you, verily, use strict and warnings! Had you followed this sage advice, you'd have known immediately that you had mistyped a variable name. `print Dumper $bbData; $e = $bbdata->[0]; print Dumper $e;` [download] On the first line, you refer to `$bbData` (with a capital D). On the second line, you refer to `$bbdata` (with a lowercase D). As to your question, you can access the element you want with `$bbData->[0][0]` or `${$bbData}[0][0]` or `$bbData->[0]->[0]` or maybe a few more I'm not thinking of. I recommend the first.	[reply] [d/l] [select]
Re^2: de-referencing @$ by kevind0718 (Scribe) on Sep 30, 2008 at 20:14 UTC
yes of course it help to use the correct variable name. OK I will start to strict and warings. Works now Many thanks. kd	[reply]
Re: de-referencing @$ by moritz (Cardinal) on Sep 30, 2008 at 19:08 UTC
`my @e = @{$bbData->[0]}; print "Col Zero: " . $e[0] . " Col One: " . $e[1] . " Col Four: " . +$e[4] . " \n" ;` [download]	[reply] [d/l]
Re: de-referencing @$ by harleypig (Monk) on Sep 30, 2008 at 19:32 UTC
You can take the first commenters solution one step further: `printf "Col Zero: %s Col One: %s Col Four: %s\n", @{ $bbdata }[0,1,4]` with appropriate changes for the data format. Harley J Pig	[reply] [d/l]
Re: de-referencing @$ by Krambambuli (Curate) on Sep 30, 2008 at 20:02 UTC
Maybe you want `my @data_elems = @{$bbData->[0]};` [download] ? Krambambuli ---	[reply] [d/l]