Java Split() vs .NET Split()

Question

Hello,

While using the Split() function I noticed the function behaves differently in Java and VB.NET. The returned array length is different. I tried using the regex split function, but I the bahvior is still not same as the java one. I was wondering if there is a method to force .NET to behave the same way as the Java one? or I have to write my own hack code?

Java Code :

                String[] test = "a".split("a");
                System.out.println("a - Array Length : " + test.length);

                String[] test2 = "ab".split("a");
                System.out.println("ab - Array Length : " + test2.length);

                String[] test3 = "ba".split("a");
                System.out.println("ba - Array Length : " + test3.length);

                String[] test4 = "cab".split("a");
                System.out.println("cab - Array Length : " + test4.length);

                String[] test5 = "caba".split("a");
                System.out.println("caba - Array Length : " + test5.length);


a - Array Length : 0
ab - Array Length : 2
ba - Array Length : 1
cab - Array Length : 2
caba - Array Length : 2

VB.NET

                dim test() As String = "a".Split("a")
                 Console.WriteLine("a - Array Length : " & test.length)

                dim test2() As String = "ab".split("a")
                 Console.WriteLine("ab - Array Length : " & test2.length)

                dim test3() As String = "ba".split("a")
                 Console.WriteLine("ba - Array Length : " & test3.length)

                dim test4() As String = "cab".split("a")
                 Console.WriteLine("cab - Array Length : " & test4.length)

                dim test5() As String = "caba".split("a")
                 Console.WriteLine("caba - Array Length : " & test5.length)

a - Array Length : 2
ab - Array Length : 2
ba - Array Length : 2
cab - Array Length : 2
caba - Array Length : 3

Thanks

Answer 1

I believe you'll need something custom to make these consistent. Java removes trailing empty strings (and also leading empty strings if the string is equal to the sub-string), whereas VB/C# always add empty strings when the sub-string is at the beginning or end of the string (unless StringSplitOptions.RemoveEmptyEntries is passed to the Split method.)

Here's an extension method that should help you get what you're after:

Module StringExtensions

    <Extension()>
    Public Function SplitJava(ByVal value As String, ByVal separator As String) As String()
        Dim segments = value.Split(separator)

        If (segments.LastOrDefault() = "") Then
            If (segments.Length = 2 And segments.First() = "") Then
                Return Array.Empty(Of String)()
            End If
            segments = segments.Take(segments.Length - 1).ToArray()
        End If

        Return segments
    End Function

End Module

Usage:

Module Program
    Sub Main(args As String())
        Dim test = "a".SplitJava("a")
        Console.WriteLine("a - Array Length : " & test.Length)

        Dim test2 = "ab".SplitJava("a")
        Console.WriteLine("ab - Array Length : " & test2.Length)

        Dim test3 = "ba".SplitJava("a")
        Console.WriteLine("ba - Array Length : " & test3.Length)

        Dim test4 = "cab".SplitJava("a")
        Console.WriteLine("cab - Array Length : " & test4.Length)

        Dim test5 = "caba".SplitJava("a")
        Console.WriteLine("caba - Array Length : " & test5.Length)
    End Sub
End Module

Answer 2

Hi Paul,

Thanks for the quick reply. I've tested your Split() method in my code and it's working perfectly just like the Java one :) .

Thanks