[RESOLVED] String manipulation _ Replace vs delete

For example http://www.vbforums.com/newthread.php?do=newthread&f=25

wanted to replace

http://www.vbforums.com to http://www.youtube.com

which would be better? Delete did not seem to work for me

vb Code:

Dim strURL As String = "http://www.vbforums.com/newthread.php?do=newthread&f=25"
strURL = strURL.Replace("http://www.vbforums.com", "http://www.youtube.com")

How odd. Well i dont understand why i used that before
for example

Code:

---

  Private _s As String = "http://www.vbforums.com/newthread.php?do=newthread&f=25"

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

 _s.Replace("http://www.vbforums.com", "http://www.youtube.com")

        MsgBox(_s)
    End Sub

---

returns same string? If i make dim as as string = _s

it works

Replace is a FUNCTION ... ir RETURNS the string with the replacements in it. Look at what Sick posted:

Code:

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strURL = strURL.Replace("http://www.vbforums.com", "http://www.youtube.com")

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Now compare that with your attempt:

Code:

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_s.Replace("http://www.vbforums.com", "http://www.youtube.com")

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In fact, if you read the documentation for string.replace, you would see that in the description it says:

Quote:

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Originally Posted by String.Replace_in_MSDN

Returns a new string in which all occurrences of a specified string in the current instance are replaced with another specified string.

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-tg

Yeh i just noticed that. thanks for the break down :)

If you are doing a lot of string replacements consider using stringbuilder

Code:

---

    Dim _sb As New System.Text.StringBuilder

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

        _sb.Append("http://www.vbforums.com/newthread.php?do=newthread&f=25")

        _sb.Replace("http://www.vbforums.com", "http://www.youtube.com")

        Debug.WriteLine(_sb.ToString)

        _sb.Length = 0 'clear the string builder
    End Sub

---

Could string builder detect and strip everything after a certain char?

example

http://www.youtube.com/watch?v=_qQpLi6tuSM

http://www.youtube.com/watch

or

<urlhere>/audio/27XQR7Tk19XD?stream_token=aMXm0

<urlhere>/audio/27XQR7Tk19XD

Not directly. You could do this but it creates strings which is what we were try to avoid.

Code:

---

    Dim sb As New System.Text.StringBuilder

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

        sb.Append("http://www.vbforums.com/newthread.php?do=newthread&f=25")

        sb.Replace("http://www.vbforums.com", "http://www.youtube.com")

        Debug.WriteLine(sb.ToString)

        Dim idx As Integer = sb.ToString.IndexOf("?")
        If idx <> -1 Then
            sb.Remove(idx, sb.Length - idx)
        End If

        Debug.WriteLine(sb.ToString)

        sb.Length = 0 'clear the string builder
    End Sub

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