AttributeError：“索引”对象没有属性“左”

Question

我尝试研究以下solution

import pandas as pd
import numpy as np
import matplotlib.pyplot as plt




my_list = [1,2,3,4,5,7,8,9,11,23,56,78,3,3,5,7,9,12]

new_list = pd.Series(my_list)

df1 = pd.DataFrame({'Range1':new_list.value_counts().index, 'Range2':new_list.value_counts().values})

df1.sort_values(by=["Range1"],inplace=True)

df2 = df1.groupby(pd.cut(df1["Range1"], [0,1,2,3,4,5,6,7,8,9,10,11,df1['Range1'].max()])).sum()

objects = df2['Range2'].index

y_pos = np.arange(len(df2['Range2'].index))


l = df2.index.categories.left.map("{:02d}".format)
r = df2.index.categories.right.map("{:02d}".format)

plt.bar(range(len(df2)), df2['Range2'].values, tick_label='('+l+', '+r+']')
plt.xticks(fontsize=6)

plt.show()

在python 2.7上，但收到以下错误消息：

 l = df1_cut.index.categories.left.map("{:02d}".format)
AttributeError: 'Index' object has no attribute 'left'

不知道如何解决并使之正常工作吗？