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

I thought I could pass the array to the sub and get back a hash right into another hash but obviously it's wrong.

Is this where I have to use reference to pass it back? 



sub sub1 {
   my %enc;
   for (@_) {
       chomp;
       if ( $_[0] =~ /^   "xxxx-(\d+):xxxxxx([^,]+),.+"$/ ) {
            $enc{$1} = $2;
       } else {
           next;
       }
   }
}


%hash1 = sub1(@dc);

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Replies are listed 'Best First'.
Re: passing @ to sub and getting back hash
by Joost (Canon) on Dec 31, 2007 at 21:04 UTC
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[d/l]
Re: passing @ to sub and getting back hash
by ysth (Canon) on Dec 31, 2007 at 21:05 UTC
    Can you describe what you want to do in English? Looping over @_ but checking $_[0] in your loop makes not a lot of sense. Did you mean $_ instead?

    "Return a hash" seems to mean different things to different people. Maybe you want return %enc;, which actually returns a list of alternating keys and values, not a hash at all, or maybe you want to return \%enc;, which returns a hashref. In either case, the caller needs to know what is going to come back and be doing the right thing with it. Your caller example is expecting a list, not a hashref.

    --
    CollegeGear.com - more than just college gear (though, yes, we have college-branded teddy bears)
[reply]
[d/l]
[select]
      $_ was the problem, let me fix it in and get back to you guys.
      You guys are the best!! thanks.
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Re: passing @ to sub and getting back hash
by runrig (Abbot) on Dec 31, 2007 at 21:05 UTC
    You need to return the hash (how else is the sub supposed to know what you want to return?).
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Re: passing @ to sub and getting back hash
by jwkrahn (Abbot) on Dec 31, 2007 at 21:22 UTC
    You don't really need a sub to do that: 
    my %hash1 = map /^   "xxxx-(\d+):xxxxxx([^,]+),.+"$/, @dc;

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[reply]
[d/l]

      Not quite so simple. Better would be:

      my %hash2 = map {/^   "xxxx-(\d+):xxxxxx([^,]+),.+"$/ ? ($1 => $2) : (
+)} @data;

      [download]
      Perl is environmentally friendly - it saves trees
[reply]
[d/l]
        How would that be "better"? 
        $ perl -MData::Dumper -le'
my @dc = ( "xxxx-123:xxxxxxABC,z", "xxxx-:xxxxxx,z", "xxxx-456:xxxxxx,
+z", "xxxx-XXX:xxxxxxDEF,z", "xxxx-789:xxxxxxGHI,z" );
my %hash1 = map /^xxxx-(\d+):xxxxxx([^,]+),.+$/, @dc;
my %hash2 = map { /^xxxx-(\d+):xxxxxx([^,]+),.+$/ ? ($1 => $2) : () } 
+@dc;
print Dumper \%hash1, \%hash2;
'
$VAR1 = {
          '123' => 'ABC',
          '789' => 'GHI'
        };
$VAR2 = {
          '123' => 'ABC',
          '789' => 'GHI'
        };

        [download]
[reply]
[d/l]
        thanks guys, my script works like a charm, but Grandpa's map statement is very stylish(i put it into my /etc/motd for now) thanks!!!!
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