python - 数据操作开始日期结束日期 python pandas

Question

我有一个促销描述数据集，其中包含有关正在运行的各种促销及其开始日期和结束日期的信息:

promo        item      start_date      end_date 

Buy1-get 1     A        2015-01-08    2015-01-12

Buy1-get 1     A        2015-02-16    2015-02-20

Buy1-40% off   B        2016-05-08      2016-05-09

现在我想组织我的数据以供后续分析，这样我就只有带有促销信息的单个可变日期。

date            item       Promo

2015-01-08       A         Buy1-get 1 

2015-01-09       A         Buy1-get 1 
2015-01-10       A         ......
2015-01-11       ....
2015-01-12

2015-02-16       A         Buy1-get 1 
2015-02-17       A         Buy1-get 1 
2015-02-18       ....      .......
2015-02-19       .....

..........
2016-05-09       B         Buy1-40% off

非常感谢任何帮助。

Answer 1

您可以使用 concat date_range 创建的所有系列与 itertuples然后 join promo 和 item 列:

df1 = pd.concat([pd.Series(r.Index,
                           pd.date_range(r.start_date,r.end_date)) for r in df.itertuples()])
        .reset_index()
df1.columns = ['date','idx']
df1 = df1.set_index('idx')
df1 = df1.join(df[['item','promo']]).reset_index(drop=True)
print (df1)
         date item         promo
0  2015-01-08    A    Buy1-get 1
1  2015-01-09    A    Buy1-get 1
2  2015-01-10    A    Buy1-get 1
3  2015-01-11    A    Buy1-get 1
4  2015-01-12    A    Buy1-get 1
5  2015-02-16    A    Buy1-get 1
6  2015-02-17    A    Buy1-get 1
7  2015-02-18    A    Buy1-get 1
8  2015-02-19    A    Buy1-get 1
9  2015-02-20    A    Buy1-get 1
10 2016-05-08    B  Buy1-40% off
11 2016-05-09    B  Buy1-40% off

另一种解决方案 melt和 groupby with resample :

df1 = df.reset_index().rename(columns={'index':'idx'})
df1 = pd.melt(df1, id_vars='idx', value_vars=['start_date','end_date'], value_name='date')
        .set_index('date')
df1 = df1.groupby('idx')
         .resample('d')
         .ffill()
         .reset_index(level=1)
         .drop(['idx','variable'], axis=1)
df1 = df1.join(df[['item','promo']]).reset_index(drop=True)
print (df1)
         date item         promo
0  2015-01-08    A    Buy1-get 1
1  2015-01-09    A    Buy1-get 1
2  2015-01-10    A    Buy1-get 1
3  2015-01-11    A    Buy1-get 1
4  2015-01-12    A    Buy1-get 1
5  2015-02-16    A    Buy1-get 1
6  2015-02-17    A    Buy1-get 1
7  2015-02-18    A    Buy1-get 1
8  2015-02-19    A    Buy1-get 1
9  2015-02-20    A    Buy1-get 1
10 2016-05-08    B  Buy1-40% off
11 2016-05-09    B  Buy1-40% off