万能的matplotlib里有pie函数，可以直接画饼图。

labels = ['Cookies', 'Jellybean', 'Milkshake', 'Cheesecake']
sizes = [38.4, 40.6, 20.7, 10.3]
plt.pie(sizes, labels=labels, autopct='%1.1f%%')
plt.legend(loc=[0.9, 0.6])
plt.axis('equal')
plt.show()

如果数据是pandas的类型，那么画饼图更容易

import pandas as pd
import matplotlib.pyplot as plt
plt.style.use('ggplot')

df = pd.DataFrame({'Country': ['china', 'india', 'usa'], 'Population': [14, 13, 3]})

df.Population.groupby(df.Country).sum().plot(kind='pie')
plt.axis('equal')
plt.legend()
plt.show()