I've been doing this for years but now and then things get befuddled in me' noggin.

USPS XML shipping response: if you request all available services for a package, you get something like

$data = { 
 'Package' => { 
 'ID' => '0', 
 'ZipDestination' => '10022', 
 'Ounces' => '0', 
 'Postage' => [ 
 { 
 'Rate' => '41.30', 
 'MailService' => 'Express Mail PO to Addressee' 
 }, 
 { 
 'Rate' => '14.40', 
 'MailService' => 'Express Mail Flat Rate Envelope (12.5" x 9.5")' 
 } 
 ], 
 'ZipOrigination' => '12345', 
 'Zone' => '8', 
 'Error' => {}, 
 'Size' => 'REGULAR', 
 'Pounds' => '11', 
 'Machinable' => 'FALSE' 
 } 
}; 

Note the bolded, this is an array to parse as in

foreach $e (@{$data->{Package}->{Postage}}) {
push (@rates, ($e->{Rate} * $num_boxes));
push (@mail, $e->{MailService});
}

So I have two neat arrays of rates and services to display.

The problem: Sometimes there is only one service available:

$data = { 
 'Package' => { 
 'ID' => '0', 
 'ZipDestination' => '12345', 
 'Ounces' => '8', 
 'Postage' => { 
 'Rate' => '127.24', 
 'MailService' => 'Parcel Post' 
 }, 
 'ZipOrigination' => '12345', 
 'Zone' => '8', 
 'Error' => {}, 
 'Size' => 'OVERSIZE', 
 'Pounds' => '62', 
 'Machinable' => 'FALSE' 
 } 
}; 

If the above method is used, 'foreach $e (@{$data->{Package}->{Postage}})' of course errors because it's not an ARRAY reference. I never know when this is going to return a single possible result, so it has to be able to identify if there's an array. I know there's got to be an easy way to identify this as an array but it fails me. if (@{$data->{Package}->{Postage}}) and if (defined(@{$data->{Package}->{Postage}})) both fail. What am I missing? :-(