Python Matplotlib：在堆叠条形图中显示列名称

给定一个数据帧：

                    response_min                                     \
device_mac                   0dd8d       1f3cc       61ff6      623ce   
datetime                                                                
2016-05-25 08:00:00       0.000000    4.250000    0.250000   0.000000   
2016-05-25 12:00:00       0.000000    0.000000    0.000000   0.000000   
2016-05-25 16:00:00       0.000000    0.000000    0.000000   0.000000   
2016-05-26 08:00:00      12.133333  119.666667    0.250000   0.000000 

通过这样做：

ax = df.plot(kind='bar',stacked=True,logy=True)

for p in ax.patches:
    ax.annotate(str(p.get_height()), (p.get_x() * 1.005, p.get_height() * 1.005))

我得到：

如何继续显示列名称而不是条内的值

非常感谢

（剧透警报）根据Stanley的建议和调试器的帮助，我成功地做到了这一点（注意：对数刻度已关闭）：

类似于这里：

import pandas as pd
import matplotlib.pyplot as plt

df=pd.DataFrame({'Devices': [ 'dev1', 'dev2', 'dev3', 'dev4'],
                 'Response': [4.25,0.,119.,12.1],})

df = df.set_index('Devices')
df.plot(kind='bar',  title='Response')
ax = df.plot(kind='bar',  title='Response')
ax.set_ylim(0, 130)
for i, label in enumerate(list(df.index)):
    height = df.ix[label]['Response']
    ax.annotate(str(label), (i, height + 0.3))

plt.show()

import pandas as pd
import matplotlib.pyplot as plt

df=pd.DataFrame({'Devices': [ 'dev1', 'dev2', 'dev3', 'dev4'],
                 'Response': [4.25,0.,119.,12.1],})

df = df.set_index('Devices')
df.plot(kind='bar',  title='Response')
ax = df.plot(kind='bar',  title='Response')
ax.set_ylim(0, 130)
for i, label in enumerate(list(df.index)):
    height = df.ix[label]['Response']
    ax.annotate(str(label), (i, height + 0.3))

plt.show()