Dereferencing a hash ref in an array ref

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

Hello Monks, I am working on a script that gets by DBI an hash ref inside an array ref. To get the field names of the SQL result I have to dereference the hash ref inside the array ref, so I can go thru any field name using foreach. No problem so long, I using the following code for doing that:

foreach my $head (@{$sth->{NAME_uc}}) {
    print $head . "\n";
}
[download]

But as I remember from the Alpaca book I mixed up two syntax styles. Each for the array ref and the hash ref. So my question now: How look the pretty code for the dereferencing in the above code?

Thanks, so long!

Comment on Dereferencing a hash ref in an array ref Download Code

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Re: Dereferencing a hash ref in an array ref by moritz (Cardinal) on Mar 26, 2010 at 08:05 UTC
But as I remember from the Alpaca book I mixed up two syntax styles. Right. But there's nothing wrong with that. I think what you have is quite readable already, though of course you can use a bit more whitespace. Perl 6 - links to (nearly) everything that is Perl 6.	[reply]
Re^2: Dereferencing a hash ref in an array ref by Schaelle (Novice) on Mar 26, 2010 at 08:32 UTC
Okay, thanks anyway. (De)Referencing in more than one "level" is quite hard for me. Greetings, Schaelle	[reply]
Re: Dereferencing a hash ref in an array ref by Anonymous Monk on Mar 26, 2010 at 07:34 UTC
What is pretty? `print join "\n", @{ $sth->{NAME_uc} }, '';` [download]	[reply] [d/l]
Re^2: Dereferencing a hash ref in an array ref by Schaelle (Novice) on Mar 26, 2010 at 07:54 UTC
I just meant that the dereferencing using for the array deref the curly brackets, and for the hash deref the dereferencing using the arrow syntax. I thought its better only to use the second one, but dont know how that have to look like. Part 1: `@{$hashref}` Part 2 ("$hashref"): `$sth->{NAME_uc}` If thats already "pretty" (one syntax style for dereferencing) my thoughts just were wrong, would be an answer too. Greetings, Schaelle	[reply] [d/l] [select]
Re^3: Dereferencing a hash ref in an array ref by Anonymous Monk on Mar 26, 2010 at 08:38 UTC
:) `use Anonymous::Monk; no ESP;` References quick reference You can only get scalars using the arrow syntax, you cant get multiple values `my $sth = { NAME_uc => [ 1 .. 2 ] }; print join "\n" , $sth->{NAME_uc}[0 ,1 ]; __END__ 2` [download] `my $sth = { NAME_uc => [ 1 .. 2 ] }; print join "\n" , @$sth->{NAME_uc}[0 ,1 ]; __END__ Not an ARRAY reference at - line 3.` [download] That is why you need curlies `my $sth = { NAME_uc => [ 1 .. 2 ] }; print join "\n" , @{ $sth->{NAME_uc} } [0 ,1 ]; __END__ 1 2` [download] The arrow-less way `my $sth = { NAME_uc => [ 1 .. 2 ] }; print join "\n" , @{ $$sth{NAME_uc} } ,'' __END__ 1 2` [download] References quick reference	[reply] [d/l] [select]