xorbits.pandas.groupby.DataFrameGroupBy.bfill

DataFrameGroupBy.bfill(limit=None)

Backward fill the values.

参数

limit (int, optional) – Limit of how many values to fill.

返回

Object with missing values filled.

返回类型

Series or DataFrame

参见

Series.bfill

Backward fill the missing values in the dataset.

DataFrame.bfill

Backward fill the missing values in the dataset.

Series.fillna

Fill NaN values of a Series.

DataFrame.fillna

Fill NaN values of a DataFrame.

实际案例

With Series:

>>> index = ['Falcon', 'Falcon', 'Parrot', 'Parrot', 'Parrot']  
>>> s = pd.Series([None, 1, None, None, 3], index=index)  
>>> s  
Falcon    NaN
Falcon    1.0
Parrot    NaN
Parrot    NaN
Parrot    3.0
dtype: float64
>>> s.groupby(level=0).bfill()  
Falcon    1.0
Falcon    1.0
Parrot    3.0
Parrot    3.0
Parrot    3.0
dtype: float64
>>> s.groupby(level=0).bfill(limit=1)  
Falcon    1.0
Falcon    1.0
Parrot    NaN
Parrot    3.0
Parrot    3.0
dtype: float64

With DataFrame:

>>> df = pd.DataFrame({'A': [1, None, None, None, 4],  
...                    'B': [None, None, 5, None, 7]}, index=index)
>>> df  
          A         B
Falcon  1.0       NaN
Falcon  NaN       NaN
Parrot  NaN       5.0
Parrot  NaN       NaN
Parrot  4.0       7.0
>>> df.groupby(level=0).bfill()  
          A         B
Falcon  1.0       NaN
Falcon  NaN       NaN
Parrot  4.0       5.0
Parrot  4.0       7.0
Parrot  4.0       7.0
>>> df.groupby(level=0).bfill(limit=1)  
          A         B
Falcon  1.0       NaN
Falcon  NaN       NaN
Parrot  NaN       5.0
Parrot  4.0       7.0
Parrot  4.0       7.0

This docstring was copied from pandas.core.groupby.generic.DataFrameGroupBy.