Choose

This function selects an element from several choices. It is available in the VB.NET programming language. It may be used in programs in this language.

Choose() provides a utility procedure for returning one of the arguments as the choice. It is a helper method—it helps us access an array in a random way.

Example

This program first calls Choose with 5 arguments: a double and 4 string literals. The value 3 indicates we want the third element. The value "Perls" is returned.

Next In the second usage of the Choose function, we use the Random type to randomly select one of the arguments to Choose.

Info The arguments to Random.Next are inclusive and exclusive, so we pass 1 and 4. Choose returns a random element.

Detail Instead of specifying the arguments to Choose directly, you can encapsulate them in an array type.

And This makes for more extensible code. You can add as many elements as you want to the array and then choose from them.

Module Module1
    Sub Main()
        ' Get the third choice in the list of choices.
        Dim result As String =
            Choose(3, "Dot", "Net", "Perls", "Com").
            ToString
        Console.WriteLine(result)

        ' Get a random choice from the three choices.
        Dim rand As Random = New Random()
        result =
            Choose(rand.Next(1, 3 + 1), "Visual", "Basic", "NET").
            ToString
        Console.WriteLine(result)
    End Sub
End ModulePerls
NET

Internals

How is Choose() implemented? It first converts the double type argument to an Integer. Then it validates the Choice array. And finally it returns the array element directly.

Also It will return Nothing if you pass an index that is out of range. This is a null value.

We looked at 2 ways to use the Choose function. The Choose function could be useful to ensure that the subscript does not throw an exception due to being out of range.