Python 2.7: Shift A Dataframe By Day And A Column Value

I have a dataframe named df1 as following: df1: a b id 2010-01-01 2 3 21 2010-01-01 2 4 22 2010-01-01 3 5 23 2010-01-01 4 6

Solution 1:

If all groups are same length (in sample 4) and DatetimeIndex is sorted:

df2=df.shift((df.index==df.index[0]).sum())print(df2)abid2010-01-01  NaNNaNNaN2010-01-01  NaNNaNNaN2010-01-01  NaNNaNNaN2010-01-01  NaNNaNNaN2010-01-02  2.03.021.02010-01-02  2.04.022.02010-01-02  3.05.023.02010-01-02  4.06.024.02010-01-03  1.04.021.02010-01-03  2.05.022.02010-01-03  3.06.023.02010-01-03  4.07.024.0

But if need shift values of index by one day:

df3=df.shift(1,freq='D')print(df3)abid2010-01-02  23212010-01-02  24222010-01-02  35232010-01-02  46242010-01-03  14212010-01-03  25222010-01-03  36232010-01-03  47242010-01-04  18212010-01-04  29222010-01-04  310232010-01-04  41124

Solution 2:

One of the way is with the help of shape if the dates are sorted i.e

df.shift(df.loc[df.index[0]].shape[0])
# Or len 
df.shift(len(df.loc[df.index[0]]))

Output :

              a    b    id
2010-01-01  NaN  NaN   NaN
2010-01-01  NaN  NaN   NaN
2010-01-01  NaN  NaN   NaN
2010-01-01  NaN  NaN   NaN
2010-01-02  2.0  3.0  21.0
2010-01-02  2.0  4.0  22.0
2010-01-02  3.0  5.0  23.0
2010-01-02  4.0  6.0  24.0
2010-01-03  1.0  4.0  21.0
2010-01-03  2.0  5.0  22.0
2010-01-03  3.0  6.0  23.0
2010-01-03  4.0  7.0  24.0