invoke operator

Invokes lambda that receives the source of invoke as tabular parameter argument.

T | invoke foo(param1, param2)

Note

See let statements for more details on how to declare lambda expressions that can accept tabular arguments.

Syntax

T | invoke function([param1, param2])

Arguments

• T: The tabular source.
• function: The name of the lambda let expression or stored function name to be evaluated.
• param1, param2 ... : additional lambda arguments.

Returns

Returns the result of the evaluated expression.

Example

The following example shows how to use invoke operator to call lambda let expression:

// clipped_average(): calculates percentiles limits, and then makes another 
//                    pass over the data to calculate average with values inside the percentiles
let clipped_average = (T:(x: long), lowPercentile:double, upPercentile:double)
{
   let high = toscalar(T | summarize percentiles(x, upPercentile));
   let low = toscalar(T | summarize percentiles(x, lowPercentile));
   T 
   | where x > low and x < high
   | summarize avg(x) 
};
range x from 1 to 100 step 1
| invoke clipped_average(5, 99)

avg_x
52