Python 使用 matplotlib 将文本添加为​​ asterix

下面是我如何实现它的，基于this个答案.

import pandas as pd
import numpy as np
pd.set_option('max_columns', None)
import matplotlib.pyplot as plt
import matplotlib as mpl

data = {
         'type_sale': ['g_1','g_2','g_3','g_4','g_5','g_6','g_7','g_8','g_9','g_10'],
         'open':[70,20,24,80,20,20,60,20,20,20],
         'closed':[30,14,20,10,10,40,10,10,10,10],
        }

df = pd.DataFrame(data, columns = ['type_sale',
                                   'open',
                                   'closed',
                                   ])

fig, axs = plt.subplots(2,2, figsize=(8,6))
plt.subplots_adjust(wspace=0.2, hspace=0.6)
df.plot(x='type_sale', kind='bar', stacked=True, title='Stacked Bar Graph by dataframe',ax=axs[0,0])
df.plot(x='type_sale', kind='bar', stacked=True, title='Stacked Bar Graph by dataframe', ax=axs[0,1])
df.plot(x='type_sale', kind='bar', stacked=True, title='Stacked Bar Graph by dataframe',ax=axs[1,0])
df.plot(x='type_sale', kind='bar', stacked=True,title='Stacked Bar Graph by dataframe', ax=axs[1,1])

plt.suptitle(t='Stacked Bar Graph by dataframe', fontsize=16)

### Changes
rect = mpl.patches.Rectangle((0.05,0.01), 0.9, 1, fill=False, color="k", lw=2, 
    zorder=1000, transform=fig.transFigure, figure=fig)
fig.patches.extend([rect])
fig.text(0.05, -0.02, '*) Source: Some institution')
fig.savefig('test.png', dpi=300, bbox_inches='tight')
####

plt.show()

Output: