take · November 15, 2012 14:38
diff --git a/gistfile1.rb b/gistfile1.rb
 # Ruby knows what you
 # mean, even if you
 # want to do math on
 # an entire Array
 cities  = %w[ London
              Oslo
              Paris
              Amsterdam
              Berlin ]
 visited = %w[Berlin Oslo]
 
 puts "I still need " +
     "to visit the " +
     "following cities:",
     cities - visited
	# Ruby knows what you
	# mean, even if you
	# want to do math on
	# an entire Array
	cities = %w[ London
	Oslo
	Paris
	Amsterdam
	Berlin ]
	visited = %w[Berlin Oslo]

	puts "I still need " +
	"to visit the " +
	"following cities:",
	cities - visited