Question

I have a List(of String()). I have written a custom comparer (implements IComparer(of string)) to do an alphanumeric sort.

Is there a way to sort the List using a given index to determine which position in the String() to sort by? In other words one time I might sort by Index = 0 and another time by Index = 3. The length of all String() in the list is the same.

For reference this question is similar to Sort List<String[]> except I am using VB.net and that question is hardwired to Index=0.

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EDIT from OP’s comments:

I started simple with the non custom comparer but I am getting an error: expression does not produce a value. Not sure what I am doing wrong.
Here is the code:

Public Shared Function SortListOfStringArray(ByVal ListOfStringArray As List(Of String()), ByVal SortByIndex As Integer) As List(Of String())
    Return ListOfStringArray.Sort(Function(x, y) x(SortByIndex).CompareTo(y(SortByIndex)))
End Function 

Answer 1

To sort a list of string arrays on a specific index in the array, you use:

Dim index As Integer = 1
list.Sort(Function(x, y) x(index).CompareTo(y(index)))

Using a custom comparer that would be:

Dim index As Integer = 1
list.Sort(Function(x, y) comparer.Compare(x(index), y(index)))