Power Query: how to create a udf-function for equation criteria

[anvg]

Hi
How to create a udf-function for equaton criteria?
It is my code for that, but one is not work at all. I received a message a udf-function is not allowed in this context

let
    source = {"part","part1","settings"},
    myEqual = (base, substr) =>
    let
       result = if Text.Contains(base,substr) then true else false
    in
       result,
    return = List.RemoveMatchingItems(source, {"part"},myEqual)
in
    return

 

[ImkeF]

If you want to use the function myEqual that takes in 2 Parameters (base and substr), these parameters must be passed to the function-call: myEqual([ParameterBase], [ParameterSubstr])

Also you should use a function for the equation criteria (Comparer.FromCulture):

= List.RemoveMatchingItems(source, {"part"}, Comparer.FromCulture("en",myEqual([Parameter1], [Parameter2])))

Not sure where the parameters shall come from at the moment, as you're starting from the list that is subject to the removal process.
It would be better if you start it from a table that contains the 2 parameters in 2 separate columns and then add a column in which you perform the List.RemoveMatchingItems-operation.

 

[anvg]

Thank you for your response.
I am sorry, but maybe I do not understand anything. Comparer.FromCulture function returns a function with two parameters which are compared and that one passes to its output a logial value of that comparison.
And also Compare.FromCulture has a second parameter as a logical type not a function type.

Indeed I can solve that task in other manner.

let
    source = {"part","part1","settings"},
    poses = List.Positions(source),
    withNull = List.Transform(poses, each if Text.Contains(source{_},"part") then null else source{_}),
    return = List.RemoveNulls(withNull)
in
    return

But I want understand where is my mistake in myEqual definition? Or it is really not permited.

 

[ImkeF]

Your function myEqual will return text for logical values (true or false). This is what the Comparer.FromCulture needs. But in order to return sth, the function needs to be fed with the parameters (base, substr).

The function List.RemoveMatchingItems requires the logical value as type any - as this means basically "I don't care" - it doesn't seem to mind being fed by a function instead. The documentation lead me to the Comparer.FromCulture: https://msdn.microsoft.com/en-us/library/mt253634.aspx
I couldn't find any other logical expression that worked here.

But neither true nor false delivered the desired result from your new example above:

A List.DoesNotContain can also be written like this: List.Select(source, each Text.Contains(_, "part")=false)

 

[anvg]

Oh, I am silly. If I cannot remove unnecessarys then I can select essentials.
Thank you very mach!