comparing keys and values in different hashes

[Anonymous Monk]

Hi monks, I basically want to compare the keys between two hashes to see which they have in common. If they have one in common I want to multiply the values of both keys together. I have managed to do the comparing part, but not sure how to multiply the values. Please can anyone help?? e.g. Ideal output;

dog = 55
cat = 12

The code;

my %hash = (

     'dog' => '5',
     'sheep' => '10',
     'cat' => '3',

  );

my %hash2 = (

      'dog' => '11',
      'budgie' => '1', 
      'cat' => '4',

  ); 

foreach (keys %hash2)    {


     if (exists $hash{$_})   {

       print "$_ exists";
  
    }

}

[fruiture]

You're very close:

foreach( keys %hash2 ){

   if( exists $hash1{$_}  ){

      print "$_ = ",$hash2{$_}*$hash1{$_},"\n";
   }
}

btw.: please don't quote numbers (like '5') if you want them to be numbers and not strings: It's both confusing and (although only in microseconds) slows perl down.

my %hash = (
    dog => 11,
    budgie => 1,
   #...
)

--
http://fruiture.de

[broquaint]

my %hash = (
  dog    => 5,
  sheep  => 10,
  cat    => 3,
);

my %hash2 = (
  dog    => 11,
  budgie => 1,
  cat    => 4,
);

print "$_: ", $hash{$_} * $hash2{$_}, "\n"
  for grep exists $hash2{$_}, keys %hash;

__output__

cat = 12
dog = 55

Be careful not to stringify your numeric values or you could get unexpected results.
HTH

_________
broquaint

[robartes]

Have a look at perldata for the syntax to access hash values.

CU
Robartes-

[Russ]

This post may be interesting to you, in comparing two hashes.

Synopsis:

my %Diffs = ((map(($_ => [$R{$_}, undef]),  grep {not exists $S{$_}} k
+eys %R)),
             (map(($_ => [undef,  $S{$_}]), grep {not exists $R{$_}} k
+eys %S)),
             (map(($_ => [$R{$_}, $S{$_}]), grep {exists $S{$_} and $R
+{$_} ne $S{$_}}  keys %R)));

Russ