一个用Python类计算车险保费的例子



  • 这个例子希望能输入费率表,定价variable 等就能实现查询。变动保费可以用短期费率因子等查出来。



  • 定义这个类打算实现以下功能

    • 输入费率表,rating factor和其对应的值,以及sum assured,就能算出相对应的保费。
    • 在保单变动的时候,通过输入movement date和短期费率表可以算出变动保费
    • 如果把两个这样的class相加,可以得到它们的保费和
    • 一个info的方法可以print出保单信息
    class premium_cal:
        # initilize with its rate_table, initial_date, rating_factors, values, sum_assured
        def __init__(self, rate_table, initial_date, rating_factors, values, sum_assured):
            self.rate_table = rate_table
            self.initial_date = initial_date
            self.rating_factors = rating_factors
            self.sum_assured = sum_assured
            self.values = values
            # filter out the required row
            for idx, i in enumerate(self.rating_factors):
                self.rate_table = self.rate_table[self.rate_table.loc[:,i] == self.values[idx]]
            if self.rate_table.shape[0] == 1:
                self.rate = self.rate_table.rate.values
            else:
                print("warning! more than one row satisfies the condition")
            # calculate the premium
            self.premium = self.rate[0] * self.sum_assured
        
        # print the infomation of the policy
        def info(self):
            info = """
            This policy starts from 
            {}
            sum assured is 
            {}
            Basic policy info
            """.format(self.initial_date, self.sum_assured)
            print(info)
            info_sub = ""
            for idx, i in enumerate(self.rating_factors):
                info_sub = info_sub +"""
                {} is {}
                """.format(i,self.values[idx])
            print(info_sub)
        
        #Calculate premium rounded to 2 digital points
        def calculate_premium(self):
        	return round(self.premium,2)
        
        # Calculate movement premium 
        def calculate_movement_premium(self, short_rate_table, movement_date):
            self.short_rate_table = short_rate_table
            self.movement_date = movement_date
            self.month_passed = (self.movement_date.year - self.initial_date.year) * 12 + self.movement_date.month - self.initial_date.month
            self.short_rate_table = self.short_rate_table[short_rate_table["Month"] == self.month_passed]
            if self.short_rate_table.shape[0] == 1:
                self.short_rate = self.short_rate_table.rate.values
            else:
                print("warning! more than one row satisfies the condition")
            return round(self.short_rate[0] * self.premium, 2)
        
        #Overload add operator
        def __add__(self, other):
            if isinstance(other, premium_cal):
                return round(self.premium,2) +round(other.premium,2) 
    


  • 查看结果

    from datetime import datetime
    initial_date = '2017-10-31'
    initial_date = datetime.strptime(initial_date, "%Y-%m-%d")
    
    calculator1 = premium_cal(rate_table, 
                initial_date = initial_date, 
                rating_factors=["car_model","car_age","past_claims"], 
                values = ["D", 0, 4], sum_assured=10000)
    
    initial_date = '2018-10-31'
    initial_date = datetime.strptime(initial_date, "%Y-%m-%d")
    
    calculator2 = premium_cal(rate_table, 
                initial_date = initial_date, 
                rating_factors=["car_model","car_age","past_claims"], 
                values = ["C", 4, 2], sum_assured=10000)
    
    print(calculator1.premium)
    
    
    movement_date = '2017-11-31'
    movement_date = datetime.strptime(initial_date, "%Y-%m-%d")
    
    
    # Calculate movement premium
    calculator1.calculate_movement_premium(short_rate_table, movement_date=movement_date)
    
    #print info
    calculator1.info()
    


  • 代码和数据附上
    compressed_file.zip


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