Use Text.StartsWith and List.Contains to efficiently build custom columns

[cmengel]

Hi!

Has anyone figured out the best way to use List.Contains in combo with Text.StartsWith in PowerQuery?

I create custom Y/N columns in PQ to make my DAX measures easier to write by filtering on these columns.

Recent example:

#"AddedEXPENSE" =

        Table.AddColumn(

            AddedALLOWED,

            "EXPENSE",

            each

                if

        //  Explicitly define EXPENSE codes

                    List.Contains(

                        {

                            "3L",

                            "3K",

                            "3O",

                            // letter "oh" NOT ZERO!!!

                            "3A",

                            "3E",

                            "3G",

                            "3B",

                            "3F",

                            "3M",

                            "3S",

                            "3J",

                            "3H"

                        },

                        [WO_LABOR_CLASS_CODE]

                    )

                then

                    "Y"

        //  Explicitly define NON-EXPENSE codes

                else if

                List.Contains(

                        {

                            "3C",

                            "3I",

                            "3V",

                            "3P",

                            "3Q",

                            "3N",

                            "3W",

                            "3X"

                        },

                        [WO_LABOR_CLASS_CODE]

                    )

                    or

                    Text.StartsWith(

                        [WO_LABOR_CLASS_CODE],

                        "A"

                    )

                    or

                    Text.StartsWith(

                        [WO_LABOR_CLASS_CODE],

                        "B"

                    )

                    or

                    Text.StartsWith(

                        [WO_LABOR_CLASS_CODE],

                        "C"

                    )

                    or

                    Text.StartsWith(

                        [WO_LABOR_CLASS_CODE],

                        "1"

                    )

                    or

                    Text.StartsWith(

                        [WO_LABOR_CLASS_CODE],

                        "2"

                    )

                then

                    "N"

                else if

                    [WO_LABOR_CLASS_CODE] = "NON_LABOR" then

                    "N"

        //  Catch items that are not explicitly defined or mapped

                else

                    "CLARIFY",

            type text

        ),

Notice how the first clause uses the List.Contains function.  I like this function a lot - easier to write, read, test, maintain, etc.

The second clause is more verbose and terribly inefficient to write, read, process, etc.

My objective is to write the second clause in such a way that I can use the Text.StartsWith function and provide a List.Contains function.  I think it'll speed up my query (and shorten it!).

I'm not a PQ / M code expert.  Any help suggestions is greatly appreciated.  Thanks in advance!

PS - I've taken to writing my PowerQuery stuff in Visual Studio Code and it is a GREAT way to work!  Highly recommend - especially for newbies like me!

Cheer!
Chris

[edhans · Accepted solution]

You can just use this formula @cmengel if I am reading your requirements correctly:

List.Contains({"A", "S"}, Text.Start([Column1], 1))

That returns a true or false if the text in column1 starts with an A or S, but not an R. So to make it part of your overall function:

#"AddedEXPENSE" =
        Table.AddColumn(
            AddedALLOWED,
            "EXPENSE",
            each
                if
        //  Explicitly define EXPENSE codes
                    List.Contains(
                        {
                            "3L",
                            "3K",
                            "3O",
                            // letter "oh" NOT ZERO!!!
                            "3A",
                            "3E",
                            "3G",
                            "3B",
                            "3F",
                            "3M",
                            "3S",
                            "3J",
                            "3H"
                        },
                        [WO_LABOR_CLASS_CODE]
                    )
                then
                    "Y"
        //  Explicitly define NON-EXPENSE codes
                else if
                List.Contains(
                        {
                            "3C",
                            "3I",
                            "3V",
                            "3P",
                            "3Q",
                            "3N",
                            "3W",
                            "3X"
                        },
                        Text.Start([WO_LABOR_CLASS_CODE], 2)
					)
                then
                    "N"
                else if
                    [WO_LABOR_CLASS_CODE] = "NON_LABOR" then
                    "N"
        //  Catch items that are not explicitly defined or mapped
                else
                    "CLARIFY",
            type text
        ),

[watkinnc]

That's pretty slick, Ed! 

[cmengel]

Thank you @edhans !  This worked perfectly!  Greatly appreciated.  Have an excellent day!

[edhans]

Glad to help @cmengel 

[watkinnc]

I would use this "else if" instead of the "or"s:

else if List.Contains({"A", "B", "C", "1", "2"}, Text.ToList(Text.Start([WO_LABOR_CLASS_CODE], 1))) then "N" else if...

--Nate

If you

[cmengel]

Hey, @watkinnc !  Thanks for the reply.  I found the Text.ToList function unneccessary in this case.

Appreciate you taking the time!