这是我的答案
f,a = plt.subplots(2,2,figsize=(8,8))
f.subplots_adjust(wspace = .8)
coursera_df_beginner["course_Certificate_type"].value_counts().plot(kind='pie',
shadow=True,
explode=(0.1, 0, 0),
startangle=90,
autopct='%1.1f%%', ax=a[0,0])
a[0,0].set_title('Beginner Course')
a[0,0].set_ylabel('');
coursera_df_intermediate["course_Certificate_type"].value_counts().plot(kind='pie',
shadow=True,
explode=(0.1, 0, 0),
startangle=90,
autopct='%1.1f%%', ax=a[0,1])
a[0,1].set_title('Intermediate Course')
a[0,1].set_ylabel('');
coursera_df_mixed["course_Certificate_type"].value_counts().plot(kind='pie',
shadow=True,
explode=(0.1,),
startangle=90,
autopct='%1.1f%%',
ax=a[1,0])
a[1,0].set_title('Mixed Course')
a[1,0].set_ylabel('');
coursera_df_advanced["course_Certificate_type"].value_counts().plot(kind='pie',
shadow=True,
explode=(0.1, 0),
startangle=90,
autopct='%1.1f%%',
ax=a[1,1])
a[1,1].set_title('Advanced Course')
a[1,1].set_ylabel('');