How to use Funcction.Invoke with a variable instead of the function name?

[jmdh]

Hi,

I am trying to use the Invoke.Function like this

functionToExecute="List.First",

result = Function.Invoke(functionToExecute, {parameter list})

instead of 

Function.Invoke(List.First , {parameter list})

Obviously, this won't work, but i wonder how to achieve it...

Many thanks

[MarcelBeug · Accepted solution]

You need Expression.Evaluate.

As an example I created Query1 with a list 1-10 and Query2 with functions, parameters and the invoked function:

Query1:

{1..10}

Query2 (edited version: you need to add &[Quer1=Query1] to #shared in order to have the results loaded into the data model):

let
    Source = #table(type table[Function = text, Parameters = {any}],{{"List.Sum",{"Query1"}},{"List.FirstN",{"Query1",5}}}),
    #"Added Custom" = Table.AddColumn(Source, "Invoked Function", each Expression.Evaluate("Function.Invoke(" & [Function] & ",{" & Text.Combine(List.Transform([Parameters], Text.From),", ") & "})",#shared&[Query1=Query1]))
in
    #"Added Custom"

It looks like (before the edit):

[jmdh]

Thank you Marcel, (again)

This is hvery helpful since it shows a good example of how to write Expression.Evaluate (which i had tried without successs thanks to a previous post of yours)  and also the use of #shared.

Do you know where i could find documentation about #shared?

regards

jmdh

PS funny i have an error on the first function, not the second: good for my brain

[MarcelBeug]

Simply search for Power Query #shared and you get lots of information, e,g, from:

Reza Rad

Ken Puls

[jmdh]

Stupid of me, the List 1 to 10 was not numeric. now it works;