title | description | ms.reviewer | ms.topic | ms.date |
---|---|---|---|---|
series_fill_forward() |
Learn how to use the series_fill_forward() function to perform a forward fill interpolation of missing values in a series. |
alexans |
reference |
01/26/2023 |
Performs a forward fill interpolation of missing values in a series.
An expression containing dynamic numerical array is the input. The function replaces all instances of missing_value_placeholder with the nearest value from its left side other than missing_value_placeholder, and returns the resulting array. The leftmost instances of missing_value_placeholder are preserved.
series_fill_forward(
series,
[ missing_value_placeholder ])
[!INCLUDE syntax-conventions-note]
Name | Type | Required | Description |
---|---|---|---|
series | dynamic |
✔️ | An array of numeric values. |
missing_value_placeholder | scalar | Specifies a placeholder for missing values. The default value is double( null) . The value can be of any type that will be converted to actual element types. double (null), long (null) and int (null) have the same meaning. |
series with all instances of missing_value_placeholder filled forwards.
Note
- If you create series using the make-series operator, specify null as the default value to use interpolation functions like
series_fill_forward()
afterwards. See explanation. - If missing_value_placeholder is
double
(null), or omitted, then a result may contain null values. To fill these null values, use other interpolation functions. Only series_outliers() supports null values in input arrays. series_fill_forward()
preserves the original type of the array elements.
[!div class="nextstepaction"] Run the query
let data = datatable(arr: dynamic)
[
dynamic([null, null, 36, 41, null, null, 16, 61, 33, null, null])
];
data
| project
arr,
fill_forward = series_fill_forward(arr)
Output
arr |
fill_forward |
---|---|
[null,null,36,41,null,null,16,61,33,null,null] | [null,null,36,41,41,41,16,61,33,33,33] |
Use series_fill_backward or series-fill-const to complete interpolation of the above array.