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.


series_fill_const(x, constant_value[, missing_value_placeholder])

  • Will return series x with all instances of missing_value_placeholder replaced with constant_value.


  • x: dynamic array scalar expression that is an array of numeric values.
  • constant_value: the value replacing missing values.
  • missing_value_placeholder: optional parameter that specifies a placeholder for a missing value to be replaced. Default value is double(null).


  • If you create the series using the make-series operator, it fills in the missing values using default 0. Alternatively, you can specify a constant value to fill in by specifying default = DefaultValue in the make-series statement.
make-series num=count() default=-1 on TimeStamp from ago(1d) to ago(1h) step 1h by Os, Browser
  • To apply any interpolation functions after make-series, specify null as a default value:
make-series num=count() default=long(null) on TimeStamp from ago(1d) to ago(1h) step 1h by Os, Browser
  • The missing_value_placeholder can be of any type, which will be converted to actual element types. As such, either double(null), long(null) or int(null) have the same meaning.
  • The function preserves original type of the array elements.


let data = datatable(`arr`: dynamic)
| project arr, 
          fill_const1 = series_fill_const(arr, 0.0),
          fill_const2 = series_fill_const(arr, -1)  
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]