series_fill_const()

  • Article
  • 03/28/2025

Applies to: ✅ Azure Data Explorer ✅ Azure Monitor ✅ Microsoft Sentinel

Replaces missing values in a series with a specified constant value.

Takes an expression containing dynamic numerical array as input, replaces all instances of missing_value_placeholder with the specified constant_value and returns the resulting array.

Syntax

series_fill_const(series, constant_value, [ missing_value_placeholder ])

Learn more about syntax conventions.

Parameters

Name Type Required Description
series dynamic ✔️ An array of numeric values.
constant_value scalar ✔️ The value used to replace the missing 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 is 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 replaced with constant_value.

Note

  • If you create series using the make-series operator, specify null as the default value to use interpolation functions like series_fill_const() afterwards. See explanation.
  • If missing_value_placeholder is double(null), or omitted, then a result contains null values. To fill these null values, use other interpolation functions. Only series_outliers() supports null values in input arrays.
  • series_fill_const() preserves the original type of the array elements.

Example

The following example replaces the missing values in the datatable, data, with the value 0.0 in column fill_const1 and with the value -1 in column fill_const2.

let data = datatable(arr: dynamic)
    [
    dynamic([111, null, 36, 41, 23, null, 16, 61, 33, null, null])   
];
data 
| project
    arr, 
    fill_const1 = series_fill_const(arr, 0.0),
    fill_const2 = series_fill_const(arr, -1)

Output

arr fill_const1 fill_const2
[111,null,36,41,23,null,16,61,33,null,null] [111,0.0,36,41,23,0.0,16,61,33,0.0,0.0] [111,-1,36,41,23,-1,16,61,33,-1,-1]

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