decompress a pattern in VB.net

Question

I am still very new to dotNET, and I have searched and searched, and racked my brain trying to figure this out.

I have a pattern as a string which looks like this :

3(a)-bab-4(c)-aab-7(d)-abab                       <---- pattern is always different and can be up to 50 or 60 characters

What I need is:

aaababccccaabdddddddabab

Can someone please help me figure this out?

Answer 1

Well, it looks like a RLE, split your string by '-', then check if contains '(', if so, take the number, extract the text and repeat in a loop

Dim sb As New StringBuilder()

Dim parts As String() = inputString.Split("-"C)

For Each part As String In parts

    Dim indexOfPar As Integer = part.IndexOf("(")

    If indexOfPar = -1 Then
        sb.Append(part)
    Else
        Dim repeat As Integer = Integer.Parse(part.Substring(0, indexOfPar))

        Dim toRepeat As String = part.Substring(indexOfPar, part.Length - (indexOfPar - 2))
        '-2 to remove ()
        For buc As Integer = 0 To repeat - 1
            sb.Append(toRepeat)
        Next

    End If

Next

Return sb.ToString()

Answer 2

Here is a function that will work with the example that you gave. It is using String.Split and String.Replace to parse out your Data.

Module Module1

    Sub Main()
        Dim testValue As String = "3(a)-bab-4(c)-aab-7(d)-abab"
        Console.WriteLine(testValue)
        Console.WriteLine(ParseData(testValue))
        Console.ReadLine()
    End Sub

    Public Function ParseData(value As String) As String
        Dim temp As String = ""
        Dim result As String = ""
        Dim splitChar As Char() = {"-"c}
        Dim split() As String = value.Split(splitChar, StringSplitOptions.RemoveEmptyEntries)
        For Each section In split
            If (IsNumeric(section(0))) Then 'Check to see if section starts with a number
                Dim tmpvalue1() As String = section.Split(New Char() {"("c}) 'Check if section contains a paren
                If tmpvalue1.Length > 0 Then 'If so then replace them and strip out the number to get to the repeating characters
                    Dim validChar As String = section.Replace("(", "").Replace(")", "").Replace(tmpvalue1(0), "")
                    Dim count As Integer
                    If Integer.TryParse(tmpvalue1(0), count) Then
                        temp = validChar
                        For x = 0 To count - 2
                            temp += validChar
                        Next
                    End If
                End If
                result += temp
            Else
                result += section
            End If

        Next
        Return result
    End Function

End Module

Result: