foreach $field (@Fields) { # <- age and surname in this case
   scalar(@Persons)==0 && return 0;
   for ($i=0;$i<scalar(@Persons);$i++) { 
       ($Persons[$i]->{$field->{key}} eq $field->{content}) && next;
       # when a match field can not be found in a dataset  element, the dataset element can be removed from 

       # the dataset since all match fields have to be found in the dataset element this way the dataset element
       # does not have to be considdered in the next 
       # iteration (next match field)

        splice(@Persons,$i,1);
        $i--;
   }
}
#return...