How to Get the Positions of Strings Filtered by Multi-Split Without using (MyString.IndexOf(part, p))

Question

Regarding the previous question MyQuestions There was no expected result due to the duplicate string between the splits. I want to achieve a very correct result with these two functions. thank

'ResultPosition {"54-58","60-64") This output is correct

    Sub Loading()
        Dim MultiSplit As String() = {"C", "B", "A"}
        Dim MyString As String = "}666[]777([}666[]777(]00[A]1111{C}22(B)33333{C}4{C}5{C}666[A]777(B)8(B)99{C}999[A]101010}666[]777("
        'ResultPosition {"54-58","60-64") This output is correct
        Dim ResultPosition As String() = GetPositionsByMultiSplit(MyString, MultiSplit.ToList)
    End Sub

    Dim CurrentPosition As Integer = 0
    Dim LisPosition As New List(Of String)
    Function fWhere(inPart As String, idx As Integer, Finditem As String(), idxOfMultiSplit As Byte) As Boolean
        CurrentPosition += inPart.Length + Finditem(idxOfMultiSplit).Length
        If idxOfMultiSplit = Finditem.Count - 1 OrElse inPart.Contains(Finditem(idxOfMultiSplit + 1)) Then
            Return True
        Else
            Return False
        End If
    End Function
    Function GetPositionsByMultiSplit(BodyText As String, MultiSplit As List(Of String)) As String()
        Dim result = New List(Of String) From {BodyText}
        Dim p As Integer = 0  ' Start position for searching
        For i = 0 To MultiSplit.Count - 1
            Dim item = MultiSplit(i)
            result = result.
                SelectMany(Function(str) Split(str, item, Compare:=CompareMethod.Text)).
                Where(Function(part, idx) fWhere(part, idx, MultiSplit.ToArray, i)).
                ToList()
        Next
        Dim positions = result.
            Select(Function(part)
                       Dim startIndex = BodyText.IndexOf(part, p)
                       Dim endIndex = startIndex + part.Length - 1
                       p = endIndex + 1  ' Move start position to after the found part
                       Return $"{startIndex}-{endIndex}"
                   End Function).
            ToArray()
        Return positions
    End Function

Answer 1

Hi @Mansour_Dalir ,

You can try creating a separate array of record positions, and record the position of the result after each split.

Here is an example.

    Function MultiFinderStringPositions(BodyText As String, MultiFind As List(Of String)) As String()
        Dim result1 As String() = {BodyText}
        Dim result2 As String() = {}
        Dim result3 As String() = {}
        Dim startindex As Integer = 0
        Dim positions1 As Integer() = {}
        Dim positions2 As Integer() = {}
        For Each item In MultiFind
            Dim idx As Integer = MultiFind.IndexOf(item)
            If idx = MultiFind.Count - 1 Then
                For i = 0 To result1.Length - 1
                    Dim res As String() = result1(i).Split(item)
                    result2 = result2.Concat(res).ToArray
                    For Each str As String In res
                        positions2 = positions2.Append(result1(i).IndexOf(str, startindex) + positions1(i)).ToArray
                        startindex = result1(i).IndexOf(str, startindex) + str.Length - 1
                    Next
                    startindex = 0
                Next
            Else
                For i = 0 To result1.Length - 1
                    Dim res As String() = result1(i).Split(item).Where(Function(f) f Like "*" & MultiFind(idx + 1) & "*").Select(Function(f) f).ToArray
                    result2 = result2.Concat(res).ToArray
                    For Each str As String In res
                        If idx = 0 Then
                            positions2 = positions2.Append(BodyText.IndexOf(str, startindex)).ToArray
                            startindex = BodyText.IndexOf(str, startindex) + str.Length - 1
                        Else
                            positions2 = positions2.Append(result1(i).IndexOf(str, startindex) + positions1(i)).ToArray
                            startindex = result1(i).IndexOf(str, startindex) + str.Length - 1
                        End If
                    Next
                    startindex = 0
                Next
                startindex = 0
                result1 = result2
                result2 = {}
                positions1 = positions2
                positions2 = {}
            End If
        Next
        For i = 0 To result2.Length - 1
            result3 = result3.Append((positions2(i) & "-" & (positions2(i)) + result2(i).Length - 1).ToString).ToArray
        Next
        Return result3
    End Function

Best Regards.

Jiachen Li

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