Question

I want to build a comma delimited string from Range A1:A400.

What is the best way of doing this? Should I use a For loop?

Answer 1

The laziest way is

s = join(Application.WorksheetFunction.Transpose([a1:a400]), ",")

This works because .Value property of a multicell range returns a 2D array, and Join expects 1D array, and Transpose is trying to be too helpful, so when it detects a 2D array with just one column, it converts it to a 1D array.

In production it is advised to use at least a little bit less lazy option,

s = join(Application.WorksheetFunction.Transpose(Worksheets(someIndex).Range("A1:A400").Value), ",")

otherwise the active sheet will always be used.