1. pandas 实现sql row number 功能
先按照id和msg_ts排序, 然后按照id topic分组,row number功能就现实了
df['row_num'] = df.sort_values(['id', 'msg_ts'], ascending=True).groupby(['id', 'topic']).cumcount() + 1
padans链接:
https://pandas.pydata.org/pandas-docs/stable/getting_started/comparison/comparison_with_sql.html