I m in a situation where i have a large number of dictionaries or hashes (around 30) to deal with and each having variable number of elements.. But i have to apply the same operation to all the elements of all the hashes.
       To do this, i tried to store all the hash names in an array and then i looped through the array and use each name to call that respective dictionary. But i got a syntax error for that.
     My code looked something like..
     foreach $name( @array)
     {
        foreach $key (keys(%$name))
         {
            print "$key : $$name{$key}";
          }
      }

Can i somehow modify this to make it work? or could u please suggest some other way to handle all those dictionaries without having to cut paste my code 30 times and modifying it...

You need references to the hashes, not just the hash names:

Code:

my %foo = (1..10); my %bar = (11..20); my @hashes = (\%foo, \%bar); foreach my $hashref (@hashes) {   foreach my $key (keys %{$hashref}) {      print "$key = $hashref->{$key}\n";   } }

On an important side-note, make sure you are using the "strict" and "warnings" pragmas when writing your perl code.





I agree that a list of hash references is much the best way, Kevin, and I suggest that our poster goes that way.  But it is possible to store just the names in a list:

Code:

%first = ("Graham" => "Melksham", "Chris" => "Beach", "Martin" => "Melksham"); %second = ("Lisa" => "Melksham", "Leah" => "Melksham"); @lohash = ("first","second"); foreach $hname(@lohash) {        %hd = %$hname;        print %hd,"\n";        }

Which runs as:

Code:

Dorothy:dec07 grahamellis$ perl sl MartinMelkshamChrisBeachGrahamMelksham LisaMelkshamLeahMelksham Dorothy:dec07

Yes, that is true, it is possible. But as you agree, the recommended method is to use hard references (as in my example)  so the OP should stick with that to avoid problems that soft references can introduce.

hi ,
          i tried the code that graham posted and it works.. (duh!). But how is it different from the code that i posted in my original question?..  instead of using storing my hash name in a separate variable i have directly used
 
 foreach $key(keys(%$array[$i]))
 {
  .....
  }

Why does that make a difference??

Missing curley braces to scope the variable.   This works ... (extended example):

Quote:

%first = ("Graham" => "Melksham", "Chris" => "Beach", "Martin" => "Melksham"); %second = ("Lisa" => "Melksham", "Leah" => "Melksham"); @lohash = ("first","second"); foreach $hname(@lohash) {   %hd = %$hname;   print %hd,"\n";   } for ($i=0; $i<=$#lohash; $i++) { foreach $key(keys(%{$lohash[$i]})) {        print $i,$key,"\n";        }}

But it remains better to write the code in the manner Kvin suggested.

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