The Choose function lets you often make more concise, albeit not faster, code, because it lets you replace a lengthy Select Case block. For example, the following code:
Select Case index Case 1 result = 100 Case 2 result = 250 Case 3 result = 400 Case 4 result = 500End Selectcan be replaced by the more concise:
result = Choose(index, 100, 250, 400, 500)If the index is less than one or higher than the number of values, the Choose function returns Null. Here’s another way to use the Choose function in place of a If…ElseIf block:
' the standard wayIf x < y Then result = 100Elseif x = y Then result = 150Else result = 400End If' the more concise wayresult = Choose(Sgn(x - y) + 2, 100, 150, 400)Finally, the Choose function is often useful to quickly initialize an array of number or strings:
' the standard wayDim names(1 To 5) As Stringnames(1) = "Robert"names(2) = "Patrick"names(3) = "Timothy"names(4) = "James"names(5) = "Frank"' the more concise wayDim names(1 To 5) As String, i As IntegerFor i = 1 To 5 names(i) = Choose(i, "Robert", "Patrick", "Timothy", "James", "Frank")NextIt is evident that the more array elements you must initialize, the more code you save using this technique.
However, in all cases you should keep in mind that the Choose function is always slower than the Select Case or If block it is meant to replace, therefore it shouldn’t be used in time-critical loops.
