2.4 Missing Data

The missing data docs.

Fill forward a reversed timeseries

In [1]: df = pd.DataFrame(np.random.randn(6,1), index=pd.date_range('2013-08-01', periods=6, freq='B'), columns=list('A'))

In [2]: df.ix[3,'A'] = np.nan

In [3]: df
Out[3]: 
                   A
2013-08-01  0.469112
2013-08-02 -0.282863
2013-08-05 -1.509059
2013-08-06       NaN
2013-08-07  1.212112
2013-08-08 -0.173215

In [4]: df.reindex(df.index[::-1]).ffill()
Out[4]: 
                   A
2013-08-08 -0.173215
2013-08-07  1.212112
2013-08-06  1.212112
2013-08-05 -1.509059
2013-08-02 -0.282863
2013-08-01  0.469112

cumsum reset at NaN values