pandas-level index

data.set_index(['Region', 'Country'], inplace=True)
# data.set_index(['Country', 'Region'], inplace=True)
data

# 外层选取
data.loc['Western Europe']

# 内层选取
data.loc['Australia and New Zealand', 'New Zealand']

#交换层级顺序
data.swaplevel()

#层级索引排序
data.sort_index(level=1)