Posts tagged: reference

  • Looping through key/value pairs from a Perl scalar hash reference

    If you’ve got a hash ( %hash ), it’s easy enough to loop through all the key/value pairs with the following:

    foreach my $key ( keys %hash )
    {
    print "key: $key, value: $hash{$key}\n";
    }

    We could reference the hash with:

     $href = \%hash; 

    As the hash element is scalar, the $ notation is used.

    To access the key/value pairs in a hash reference, the syntax differs slightly from the first example.

    foreach my $key ( keys %{ $href } )
    {
    print "key: $key, value: ${$href}{$key}\n";
    }

    Perlreftut contains a more in depth explanation of Perl references.

    September 13, 2011 - 1 minute read - perl looping key value pairs hash reference scalar