日期格式无法作为日期处理

Question

请在type( df1['Date'])为班级pandas.core.series.Series且df1 ['日期'] [0]为浮点数时出现以下错误，请提供任何帮助：

AttributeError: 'int' object has no attribute 'toordinal'

 for i in range(2266,df1.shape[0],1):

            performance[i]=performance[i-1]*(1+r[i])
 df1['performance']=performance
 print(performance[2267])
 plt.plot(df1['Date'][2265:4616],df1['performance'][2265:4616])