Pandas笔记：设置索引

1import pandas as pd
2 
3df = pd.DataFrame({"month": [1, 4, 7, 10],
4                   "year": [2012, 2014, 2013, 2014],
5                   "sale": [55, 40, 84, 31]})
6new_df = df.set_index(["year", "month"])
7print(new_df.index.names)
8print(new_df.index.levels)
9 
10
11['year', 'month']
12[[2012, 2013, 2014], [1, 4, 7, 10]]