缺失数据(Missing Data)

The missing data docs.

Fill forward a reversed timeseries

  1. In [79]: df = pd.DataFrame(np.random.randn(6,1), index=pd.date_range('2013-08-01', periods=6, freq='B'), columns=list('A'))
  3. In [80]: df.loc[df.index[3], 'A'] = np.nan
  5. In [81]: df
  6. Out[81]: 
  7.                    A
  8. 2013-08-01 -1.054874
  9. 2013-08-02 -0.179642
  10. 2013-08-05  0.639589
  11. 2013-08-06       NaN
  12. 2013-08-07  1.906684
  13. 2013-08-08  0.104050
  15. In [82]: df.reindex(df.index[::-1]).ffill()
  16. Out[82]: 
  17.                    A
  18. 2013-08-08  0.104050
  19. 2013-08-07  1.906684
  20. 2013-08-06  1.906684
  21. 2013-08-05  0.639589
  22. 2013-08-02 -0.179642
  23. 2013-08-01 -1.054874

cumsum reset at NaN values

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