python之pandas的层级索引与数据重构

import numpy as np
import pandas as pd

#层级索引
s1 = pd.Series(np.random.randint(-5,10,12),index=[list('aaabbbcccddd'),[1,2,4,1,2,3,1,2,3,1,2,3]])
print(s1)


#数据重构   -1 和 0代表：外索引和内索引，谁是多维数组的索引
#如果没有相同部分用nan值填充
# 将series转为dataframe
d1 = s1.unstack(0)
print(s1.unstack(0))


# 将dataframe对象转换成series对象
print(d1.stack())