Question

For example, suppose I have

{={1,2,3,4,5}}

in a cell. Is there any way to find out how many elements are in that array, and what those elements are?

Now implementing @chris neilsen’s idea, I’ve now got a VBA function as below

Function rinfo(r As Range) As String
    With r.CurrentArray
        rinfo = .Address & ", " & .Rows.Count & ", " & .Columns.Count & ", " & .Value & ", " & .Value2
    End With
End Function

however the data from it doesn’t look to hopeful, viz

$A$29, 1, 1, 1, 1

The Rows.Count and Columns.Count make sense if they are counting the rows and cols used in the worksheet. But as an indication of the data in the array formula, no.

Answer 1

Your formula only occupies a single cell, and a cell can only contain a scalar value, so after the cell has been calculated it will contain 1.
But you can evaluate the formula from VBA and that can give you an array result. If your formula is in A1 then

Dim vArr As Variant
vArr = Evaluate(Range("a1").Formula)

will result in vArr containing an array of of 4 variants of the 4 numbers.
There are several “quirks” to the Evaluate method: see one of my web pages for details.