Pandas fillna with an incremented value

问题

I have a dataframe with a column of sequential but not adjacent numbers and missing values.

I'd like to use the fillna function to fill in the missing values with an incremented value from the previous non-missing row.

Here's a simplified table:

index  my_counter
0      1
1      2
2      NaN
3      3
4      NaN
5      NaN
6      8

I'd like to fill in my_counter as such:

index  my_counter
0      1
1      2
2      2.1
3      3
4      3.1
5      3.2
6      8

How can I accomplish this task?

回答1:

IIUC ffill with groupby cumcount

df.my_counter.ffill()+df.groupby(df.my_counter.notnull().cumsum()).cumcount()/10
Out[92]: 
0    1.0
1    2.0
2    2.1
3    3.0
4    3.1
5    3.2
6    8.0
dtype: float64

来源：https://stackoverflow.com/questions/52416574/pandas-fillna-with-an-incremented-value