Imports System
Imports System.Collections.Generic

Module SlicesExample
    Sub Main()
        ' In Visual Basic .NET, we use Lists instead of slices.
        ' Lists are similar to slices in that they are dynamic arrays.

        ' An uninitialized List is not null, but has a count of 0.
        Dim s As New List(Of String)()
        Console.WriteLine($"uninit: {String.Join(", ", s)} {s Is Nothing} {s.Count = 0}")

        ' To create an empty List with non-zero capacity, we can use the constructor.
        s = New List(Of String)(3)
        Console.WriteLine($"emp: {String.Join(", ", s)} len: {s.Count} cap: {s.Capacity}")

        ' We can set and get just like with arrays.
        s.Add("a")
        s.Add("b")
        s.Add("c")
        Console.WriteLine($"set: {String.Join(", ", s)}")
        Console.WriteLine($"get: {s(2)}")

        ' Count returns the length of the List as expected.
        Console.WriteLine($"len: {s.Count}")

        ' We can add elements to the List using the Add method.
        s.Add("d")
        s.AddRange({"e", "f"})
        Console.WriteLine($"apd: {String.Join(", ", s)}")

        ' Lists can be copied. Here we create a new List and copy into it from s.
        Dim c As New List(Of String)(s)
        Console.WriteLine($"cpy: {String.Join(", ", c)}")

        ' Lists support a "range" operator with the GetRange method.
        Dim l As List(Of String) = s.GetRange(2, 3)
        Console.WriteLine($"sl1: {String.Join(", ", l)}")

        ' This gets a range up to (but excluding) index 5.
        l = s.GetRange(0, 5)
        Console.WriteLine($"sl2: {String.Join(", ", l)}")

        ' And this gets a range from index 2 to the end.
        l = s.GetRange(2, s.Count - 2)
        Console.WriteLine($"sl3: {String.Join(", ", l)}")

        ' We can declare and initialize a List in a single line as well.
        Dim t As New List(Of String)({"g", "h", "i"})
        Console.WriteLine($"dcl: {String.Join(", ", t)}")

        ' Visual Basic .NET doesn't have a built-in slices package, but we can compare Lists.
        Dim t2 As New List(Of String)({"g", "h", "i"})
        If t.SequenceEqual(t2) Then
            Console.WriteLine("t == t2")
        End If

        ' Lists can be composed into multi-dimensional data structures.
        ' The length of the inner Lists can vary.
        Dim twoD As New List(Of List(Of Integer))()
        For i As Integer = 0 To 2
            Dim innerLen As Integer = i + 1
            Dim innerList As New List(Of Integer)()
            For j As Integer = 0 To innerLen - 1
                innerList.Add(i + j)
            Next
            twoD.Add(innerList)
        Next
        Console.WriteLine($"2d: {String.Join(", ", twoD.Select(Function(x) $"[{String.Join(", ", x)}]"))}")
    End Sub
End Module