I'm new to Python so take this with moderate amounts of salt: > count = turret[station][tool_name] > count = count + 1 > turret[station][tool_name] = count 'count' is not a copy of 'turret[station][tool_name]', it's a reference. So the following should result in the same thing: > count = turret[station][tool_name] > count = count + 1 Olaf