Here's my little implementation which uses the perl map and foreach built-in's:

foreach (map{StripLTSpace($href->{$_})}@required_fields)
{
   print "Error!\n" if ($_ eq undef);
}
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In the above code, map will create a list of space stripped hash references based on each element of the required fields, and foreach will then take each element of the generated list and test if there is an undef value in the list (which of cause means missing).

Now you could split the above into two separate steps, map and then foreach, but I just like to combine them together for fun. he he he...