accessing elements of reference to hash of arrays

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

Hello, The following code successfully prints all content of a hash of arrays:

       for $x ( keys %HoA ) {
                print "$x: ";
                for $i ( 0 .. $#{ $HoA{$x} } ) {
                    print "$HoA{$x}[$i] ";
                }
       }

Output looks like this:
Keys:     array 
8001: bp ne sc ax br le no ns mn sl lt sh lw ni lu dl 
5022: bp ne sc ax br le no ns mn sl lt sh lw ni lu dl 
1018: bp ne br no lt lw ni l

I pass the %HoA to a function and want to print all the elements of th
+e %HoA—but I’m failing to do this inside the function. This is my pro
+blem.  (The same function that receives the HoA must also process an 
+array. )


some_function(\%HoA);   # could be some_function(\@array)

sub some_function{
       $aref = shift;
       if (ref($aref) eq “ARRAY”){
      
        Do something with array---I got this muchworking! 

      } elsif (ref($aref) eq “HASH”){
            
    #This foreach of the hash ref doesn't print anything!
            foreach $key ( keys %{$aref} ){
                    print “key: $key…..”;
                    for ( $i = 0; $i <=100; $i++ ){
                          print “      $aref->{$key}[$i] “;
     }
}
[download]

Thanks for any clues. John

Comment on accessing elements of reference to hash of arrays Download Code

Replies are listed 'Best First'.
Re: accessing elements of reference to hash of arrays by LanX (Saint) on Jul 10, 2014 at 20:40 UTC
> I’m failing to do this inside the function. Could you please be more specific? Did you check the passed ref with Data::Dumper to see if its populated? Did you get the keys printed? What is "failing"? Cheers Rolf (addicted to the Perl Programming Language) update Does your example even compile? I count (at least) one missing closing bracket.	[reply]
Re^2: accessing elements of reference to hash of arrays by johnguillory (Initiate) on Jul 10, 2014 at 21:36 UTC
LanX, I found my mistake after trying dumper. I wasn't even passing the correct hash into the function. Geez. Thank you! John	[reply]
Re: accessing elements of reference to hash of arrays by Laurent_R (Canon) on Jul 10, 2014 at 20:45 UTC
Hi, I would suggest, for a start, that you change this part: `} elsif (ref($aref) eq “HASH”){ #This foreach of the hash ref doesn't print anything! foreach $key ( keys %{$aref} ){` [download] to something like this: `} elsif (ref($aref) eq “HASH”){ print "Entering the hashref branch: \n"; foreach $key ( keys %{$aref} ){ # ... } else { print "Not entering the hashref branch: ", ref($aref), "\n +";` [download] At least, this will give you a disgnostic from where to continue. Or, else, you might also use the Perl debugger. Or the Data::Dumper module.	[reply] [d/l] [select]
Re: accessing elements of reference to hash of arrays by kcott (Archbishop) on Jul 11, 2014 at 14:13 UTC
G'day John, Look very carefully at the double-quotes in the code that you posted. Compare: `$ perl -Mstrict -Mwarnings -le 'my $x = []; print ref($x) eq "ARRAY" ? + q{aref} : q{other}' aref` [download] with: `$ perl -Mstrict -Mwarnings -le 'my $x = []; print ref($x) eq “ARRAY” ? + q{aref} : q{other}' Unrecognized character \xE2; marked by <-- HERE after ef($x) eq <-- HE +RE near column 30 at -e line 1.` [download] Perhaps the editor you're using has some sort of auto-correct or smart-quote mechanism configured. -- Ken	[reply] [d/l] [select]

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