在熊猫中取样数据框
问题描述：
鉴于按月索引的数据框，我希望按日索引（上采样）。以前按月索引的值现在应该除以该月份的天数。
Given a dataframe indexed by month, I'd like to reindex by day (upsample). Values that were previously indexed by month should now be divided by the number of days in the month.
答
尝试：
tidx_m = pd.date_range('2011-01-31', periods=2, freq='M')
tidx_d = pd.date_range('2011-01-01', '2011-02-28', freq='D')
d = pd.Series(100, tidx_m)
d.reindex(tidx_d, fill_value=0).groupby(pd.TimeGrouper('M')).transform('mean')
收益率
2011-01-01 3.225806
2011-01-02 3.225806
2011-01-03 3.225806
2011-01-04 3.225806
2011-01-05 3.225806
2011-01-06 3.225806
2011-01-07 3.225806
2011-01-08 3.225806
2011-01-09 3.225806
2011-01-10 3.225806
2011-01-11 3.225806
2011-01-12 3.225806
2011-01-13 3.225806
2011-01-14 3.225806
2011-01-15 3.225806
2011-01-16 3.225806
2011-01-17 3.225806
2011-01-18 3.225806
2011-01-19 3.225806
2011-01-20 3.225806
2011-01-21 3.225806
2011-01-22 3.225806
2011-01-23 3.225806
2011-01-24 3.225806
2011-01-25 3.225806
2011-01-26 3.225806
2011-01-27 3.225806
2011-01-28 3.225806
2011-01-29 3.225806
2011-01-30 3.225806
2011-01-31 3.225806
2011-02-01 3.571429
2011-02-02 3.571429
2011-02-03 3.571429
2011-02-04 3.571429
2011-02-05 3.571429
2011-02-06 3.571429
2011-02-07 3.571429
2011-02-08 3.571429
2011-02-09 3.571429
2011-02-10 3.571429
2011-02-11 3.571429
2011-02-12 3.571429
2011-02-13 3.571429
2011-02-14 3.571429
2011-02-15 3.571429
2011-02-16 3.571429
2011-02-17 3.571429
2011-02-18 3.571429
2011-02-19 3.571429
2011-02-20 3.571429
2011-02-21 3.571429
2011-02-22 3.571429
2011-02-23 3.571429
2011-02-24 3.571429
2011-02-25 3.571429
2011-02-26 3.571429
2011-02-27 3.571429
2011-02-28 3.571429
Freq: D, dtype: float64