vb.net find second occurrence of string

Question

_{Wednesday, April 20, 2016 7:55 PM}

I would like to find the second occurrence of string example day=tue below is working code but when the string has more than day= example Dim str As String = "day=mon jim sdasd sads asdasd ws s brown da33 aakk rryy day=tue day=wed day=thr day=fri" it returns dasd  thoughts? 

working code:

 Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click

        Dim str As String = "day=mon day=tue day=wed day=thr day=fri"
        Dim index1 As Integer = GetNthIndex(str, "day", 2)

        'MsgBox(index1)

        Dim index2 As Integer
        Dim NewStr As String = str.Substring(index1)
        index2 = NewStr.IndexOf(" ")
        Dim ss As String = NewStr.Substring(0, index2)
        MsgBox(ss)

    End Sub

    Public Function GetNthIndex(searchString As String, charToFind As Char, n As Integer) As Integer
        Dim charIndexPair = searchString.Select(Function(c, i) New With {.Character = c, .Index = i}) _
                                    .Where(Function(x) x.Character = charToFind) _
                                    .ElementAtOrDefault(n - 1)
        Return If(charIndexPair IsNot Nothing, charIndexPair.Index, -1)
    End Function

Work Smarter Not Harder

All replies (5)

_{Wednesday, April 20, 2016 8:06 PM ✅Answered}

You've declared charToFind as Char but then pass a String value to the method.  If you put Option Strict On at the top of your code you would have an error on your call of GetNthIndex().

I think that all you really need is:

Dim str As String = "day=mon day=tue day=wed day=thr day=fri"
Dim index1 As Integer = str.IndexOf("day", str.IndexOf("day") + 1)

-EDIT-

If you still want the GetNthIndex function then it could be implemented as:

Public Function GetNthIndex(searchString As String, subStringToFind As String, n As Integer) As Integer
    Dim idx As Integer = searchString.IndexOf(subStringToFind)
    Dim count As Integer = 1
    While idx > -1 AndAlso count < n
        idx = searchString.IndexOf(subStringToFind, idx + 1)
        count += 1
    End While
    Return idx
End Function

Reed Kimble - "When you do things right, people won't be sure you've done anything at all"

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_{Wednesday, April 20, 2016 9:28 PM ✅Answered}

I believe this is used with arrays "searchString.Select".

The below code appears to work but would need error handling probably.

Option Strict On

Imports System.Text.RegularExpressions

Public Class Form1

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        Me.Location = New Point(CInt((Screen.PrimaryScreen.WorkingArea.Width / 2) - (Me.Width / 2)), CInt((Screen.PrimaryScreen.WorkingArea.Height / 2) - (Me.Height / 2)))
    End Sub

    Dim str1 As String = "day=mon day=tue day=wed day=thr day=fri"
    Dim str2 As String = "day=mon jim sdasd sads asdasd ws s brown da33 aakk rryy day=tue day=wed day=thr day=fri"

    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        TextBox2.Text = GetNthIndex(str2, TextBox1.Text.Split("|"c)(0), CInt(TextBox1.Text.Split("|"c)(1)))
    End Sub

    Public Function GetNthIndex(StringToSearch As String, SearchString As String, n As Integer) As String
        Dim rgx As New Regex("\b" & SearchString & "...." & "\b")
        Dim MatchedInfo = rgx.Matches(str1)
        If MatchedInfo.Count > 0 Then
            Return MatchedInfo(n - 1).ToString
        End If
    End Function

End Class

La vida loca

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_{Thursday, April 21, 2016 12:54 PM}

Thank you,  Reed!

Work Smarter Not Harder

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_{Thursday, April 21, 2016 12:55 PM}

Thanks Monkeyboy! long time no talk,  hope all is well with you. 

Work Smarter Not Harder

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_{Thursday, April 21, 2016 5:54 PM}

Thanks Monkeyboy! long time no talk,  hope all is well with you. 

Work Smarter Not Harder

Going pretty good thanks and you too.

La vida loca