AttributeError:" object has no attribute"报错，请教如何解决？

Question

以下语句中，QBDownloaderDayPrice 继承自 QBDownloader，执行时报错AttributeError: 'QBDownloaderDayPrice' object has no attribute '_QBDownloader__flag_encoding'。请教如何解决？

import time
import datetime
import tushare as ts
import pandas as pd

class QBDownloader(object):

def __init__(self):
    self.__filename = ''
    self.__df_data = null
    self.__flag_encoding = 1

def saveto_csv(self):
    if self.__flag_encoding == 1:
        self.__df_data.to_csv(self.__filename, encoding='GBK')
    else:
        self.__df_data.to_csv(self.__filename)

class QBDownloaderDayPrice(QBDownloader):

def __init__(self):
    self.__filename = 'QBdata\\DayPrice\\dp' + time.strftime("%Y%m%d", time.localtime()) + '.csv'
    self.__df_data = self.get_df_data()
    self.__flag_encoding = 1

def get_df_data(self):
    #获取当天所有股票日价格，返回dataframe
    df_day_price = ts.get_today_all()
    return df_day_price

if name == '__main__':

obj_dl = QBDownloaderDayPrice()
obj_dl.saveto_csv()
print u'存储成功'

Answer 1

仔细查看error message就可以发现问题的。

所有attributes的名字，如果前面是两个下划线开头的_，python解释器会它实际的名字变成_<Class Name>__<Attributes Name>。

在QBDownloader类中，__flag_encoding变成了_QBDownloader__flag_encoding.

在QBDownloaderDayPrice类中，__flag_encoding变成了_QBDownloaderDayPrice__flag_encoding，saveto_csv()函数本身访问的_QBDownloader__flag_encoding被_QBDownloaderDayPrice__flag_encoding替换。所以就找不到_QBDownloader__flag_encoding了