在 Pandas 中添加日期和零填充时间序列？

Question

I have a time series dataframe that looks like this:

      Date     Var_1  Var_2  Var_3
------------------------------------
0   01/01/14    1      1       2  
1   01/08/14    2      1       3
2   01/15/14    2      1       3
3   01/22/14    1      0       3
4   01/29/14    3      0       2 

I want to extend the dates by a few weeks prior to the start date and zero pad the other variables, so that my dataframe will look like:

      Date     Var_1  Var_2  Var_3
------------------------------------
0   12/11/13    0      0       0  
1   12/18/13    0      0       0
2   12/25/13    0      0       0
3   01/01/13    1      1       2  
4   01/08/14    2      1       3
5   01/15/14    2      1       3
6   01/22/14    1      0       3
7   01/29/14    3      0       2 

Are there any built in functions in Pandas to do this, or do I to create a separate dataframe with the additional date sequence and zeros in all the other columns and then concatenate the two?

Answer 1

There is one way

df=df.set_index('Date').reindex(pd.date_range(end=df.Date.max(),freq='W-WED',periods=8),fill_value=0)
            Var_1  Var_2  Var_3
2013-12-11      0      0      0
2013-12-18      0      0      0
2013-12-25      0      0      0
2014-01-01      1      1      2
2014-01-08      2      1      3
2014-01-15      2      1      3
2014-01-22      1      0      3
2014-01-29      3      0      2