$map = {"Arad" => %w[Zerind Timisoara Sibiu], 
        "Zerind" => %w[Arad Oradea], 
	"Sibiu" => %w[Arad Oradea Fagaras RimnicuVilcea],
	"Oradea" => %w[Zerind Sibiu],
	"Timisoara" => %w[Arad Lugoj],
	"Lugoj" => %w[Mehadia Timisoara],
	"Mehadia" => %w[Dobreta Lugoj],
	"Dobreta" => %w[Mehadia Craiova],
	"Caiova" => %w[Dobreta Pitesti RimnicuVilcea],
	"RimnicuVilcea" => %w[Sibiu Pitesti Craiova],
	"Pitesti" => %w[RimnicuVilcea Bucharest Craiova],
	"Fagaras" => %w[Sibiu Bucharest],
	"Bucharest" => %w[Pitesti Giurgiu Urziceni Fagaras],
	"Giurgiu" => %w[Bucharest],
	"Urziceni" => %w[Bucharest Hirsova],
	"Hirsova" => %w[Eforie Urziceni],
	"Eforie" => %w[Hirsova],
	"Vaslui" => %w[Urziceni Iasi],
	"Iasi" => %w[Neamt Vaslui],
	"Neamt" => %w[Iasi]}

print "1:", $map.inspect
puts
print "2:", $map["Arad"].inspect
puts
print "3:", $map.keys.inspect
puts
print "4:", $map.values.inspect
puts
print "5:", $map.values_at("Arad", "Zerind")
puts
print "6:", $map.index(["Arad", "Oradea"])
puts "7:"
$map.each {|key,val| puts "#{key}/#{val.inspect}"}
puts "8:"
puts $map.select {|key,val| key > "Hello"}.inspect