Hi Auqua,
exists EXPR
Given an expression that specifies a hash element or array
element, returns true if the specified element in the hash or
array has ever been initialized, even if the corresponding
value is undefined. The element is not autovivified if it
doesn't exist.
print "Exists\n" if exists $hash{$key};
print "Defined\n" if defined $hash{$key};
print "True\n" if $hash{$key};
Was Du suchst ist wohl defined... probier mal ein bisschen
Gruß Horst