一个用Python类计算车险保费的例子

Mengkelyu

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。

Mengkelyu

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)

Mengkelyu

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()

Mengkelyu

代码和数据附上
compressed_file.zip