series_fill_backward()

Learn how to use the series_fill_backward() function to perform a backward fill interpolation of missing values in a series.

Performs a backward 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 right side (other than missing_value_placeholder), and returns the resulting array. The rightmost instances of missing_value_placeholder are preserved.

Syntax

series_fill_backward(series[,missing_value_placeholder])

Parameters

NameTypeRequiredDescription
seriesdynamic✔️An array of numeric values.
missing_value_placeholderscalarSpecifies 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.

Returns

series with all instances of missing_value_placeholder filled backwards.

Example

let data = datatable(arr: dynamic)
    [
    dynamic([111, null, 36, 41, null, null, 16, 61, 33, null, null])   
];
data 
| project
    arr, 
    fill_backward = series_fill_backward(arr)

Output

arrfill_backward
[111,null,36,41,null,null,16,61,33,null,null][111,36,36,41,16,16,16,61,33,null,null]