How to use Excel's array-formulas for a UDF to read each cell correctly?

Question

G'Day,

I have a question more towards helping myself understand how Excel's array-formulas (Control+Shift+Enter) can read each cell dynamically into the formula.

I made an simplified example to show you what I mean.

I created a small fictional farm that has some animals, listed by names and will provide the sound of what the animal makes. In the next column I made a User Defined Function called MakesSound which takes an input of what animal it is and respond the sound that animal it makes. As shown in the snapshot picture below.

Unfortunately, I thought an arrayformula could pick up that I have different cells listing the animals and it ends like this snapshot instead.

so how can I ask the arrayformula to recognise I have different cells in Column B as I know Quacks isn't the answer for other animals. :-)

Here is another snapshot showing the formulas next to arrayformulas for comparsion and code I used as well.

Public Function MakesSound(AnimalName As String) As Variant
    Select Case AnimalName
        Case Is = "Duck"
            MakesSound = "Quack!"
        Case Is = "Cow"
            MakesSound = "Moo!"
        Case Is = "Bird"
            MakesSound = "Tweet!"
        Case Is = "Sheep"
            MakesSound = "Ba-Ba-Ba!"
        Case Is = "Dog"
            MakesSound = "Woof!"
        Case Else
            MakesSound = "Eh?"
    End Select
End Function

I'm open to suggestions.

Thanks, Peter.

Answer 1

you need to make you array function read the data into an array, process it and create an output array.
Then the array function nneeds to be entered in a multi-cell array formula (D3:D7) using ctrl-shift-enter.

Public Function MakesSound(AnimalName As Range) As Variant
Dim Ansa() As Variant
Dim vData As Variant
Dim j As Long
vData = AnimalName.Value2
ReDim Ansa(1 To UBound(vData), 1 To 1)
For j = 1 To UBound(vData)
    Select Case vData(j, 1)
    Case Is = "Duck"
        Ansa(j, 1) = "Quack!"
    Case Is = "Cow"
        Ansa(j, 1) = "Moo!"
    Case Is = "Bird"
        Ansa(j, 1) = "Tweet!"
    Case Is = "Sheep"
        Ansa(j, 1) = "Ba-Ba-Ba!"
    Case Is = "Dog"
        Ansa(j, 1) = "Woof!"
    Case Else
        Ansa(j, 1) = "Eh?"
    End Select
Next j
MakesSound = Ansa
End Function