优化这段代码：降低这段代码重复率：def readCSVFile(demand_file, depot_file, model): model['demand_dict'] = {int(row['id']): Demand(id=int(row['id']), x_coord=float(row['x_coord']), y_coord=float(row['y_coord']), demand=float(row['demand']), start_time=float(row['start_time']), end_time=float(row['end_time']), service_time=float(row['service_time'])) for row in csv.DictReader(open(demand_file))} model['demand_id_list'] = list(model['demand_dict'].keys()) model['number_of_demands'] = len(model['demand_id_list']) model['vehicle_dict'] = {row['vehicle_type']: Vehicle(depot_id=row['depot_id'], x_coord=float(row['x_coord']), y_coord=float(row['y_coord']), type=row['vehicle_type'], capacity=float(row['vehicle_capacity']), free_speed=float(row['vehicle_speed']), numbers=float(row['number_of_vehicle']), fixed_cost=float(row['fixed_cost']), variable_cost=float(row['variable_cost']), start_time=float(row['start_time']), end_time=float(row['end_time'])) for row in csv.DictReader(open(depot_file))} model['vehicle_type_list'] = list(model['vehicle_dict'].keys())

可以将其中的一些重复代码提取出来，写成函数或者变量。比如：

def parse_demand_row(row):
    return Demand(id=int(row['id']),
                  x_coord=float(row['x_coord']),
                  y_coord=float(row['y_coord']),
                  demand=float(row['demand']),
                  start_time=float(row['start_time']),
                  end_time=float(row['end_time']),
                  service_time=float(row['service_time']))

def parse_vehicle_row(row):
    return Vehicle(depot_id=row['depot_id'],
                   x_coord=float(row['x_coord']),
                   y_coord=float(row['y_coord']),
                   type=row['vehicle_type'],
                   capacity=float(row['vehicle_capacity']),
                   free_speed=float(row['vehicle_speed']),
                   numbers=float(row['number_of_vehicle']),
                   fixed_cost=float(row['fixed_cost']),
                   variable_cost=float(row['variable_cost']),
                   start_time=float(row['start_time']),
                   end_time=float(row['end_time']))

demand_dict = {int(row['id']): parse_demand_row(row) for row in csv.DictReader(open(demand_file))}
demand_id_list = list(demand_dict.keys())
number_of_demands = len(demand_id_list)
vehicle_dict = {row['vehicle_type']: parse_vehicle_row(row) for row in csv.DictReader(open(depot_file))}
vehicle_type_list = list(vehicle_dict.keys())

model['demand_dict'] = demand_dict
model['demand_id_list'] = demand_id_list
model['number_of_demands'] = number_of_demands
model['vehicle_dict'] = vehicle_dict
model['vehicle_type_list'] = vehicle_type_list

这样可以大大降低代码的重复率，同时也方便了代码的维护和修改。