In this quick article, we will review the two basic techniques to handle missing values in Time Series.
The two techniques are the following :
- take the last known value and make a “forward fill”, i.e to fill the values with the last known value until a new value is met
- take the first known value after the missing values, and full the values backward
Both techniques can be illustrated this way :
To perform a forward fill, run the following command on your data frame :
df.ffill(axis = 0)
| value | date |
| 1991-07-01 | 3.526591 |
| 1991-08-01 | 3.180891 |
| 1991-09-01 | 3.252221 |
To perform a backward fill, run the following command on your data frame :
df.bfill(axis = 0)