[RESOLVED] Regex for ;\r\n

[Paulo Lib]

Hello,

I need to use regex to check if the line ends with ;\n\r (;vbCrLf).

If it doesn't end that way the vbCrLf ou vbLf is to be replaced by " "

Thank you.

[.paul.]

So if there’s no \r\n, those (nonexistent) characters should be replaced with a space? How is that supposed to work?

[Zvoni]

So if there’s no \r\n, those (nonexistent) characters should be replaced with a space? How is that supposed to work?

I understood it more in the way if the ";" (semicolon) is missing to replace a vbCrLf/vbLF with a Space, that way reversing a Linewrap.
The interesting question would be: What if the Line ends in "!\r\n" or "?\r\n" or ".\r\n" and so on?

[wqweto]

Hello,

I need to use regex to check if the line ends with ;\n\r (;vbCrLf).

If it doesn't end that way the vbCrLf ou vbLf is to be replaced by " "

Thank you.

So you want to look for vbCrLf or vbLf and replace these with " " only if they are not preceded by a ";" and regex writes itself:

1. Search for vbCrLf or vbLf -- "(\r\n|\n)"
2. For preceding ";" use negative lookbehind -- "(?<!;)(\r\n|\n)"
3. Replace with " "

private static readonly Regex MyPattern = new Regex(@"(?<!;)(\r\n|\n)", RegexOptions.Compiled);
MyPattern.Replace(TextFromFile, " ");

Edit: You can even use "(\r?\n)" for vbCrLf or vbLf search i.e. "(?<!;)(\r?\n)" for complete pattern.

cheers,
</wqw>

[Paulo Lib]

So if there’s no \r\n, those (nonexistent) characters should be replaced with a space? How is that supposed to work?

The line is (for example):

WyomingvbCrLf
is a State;vbCrLf

what I'm asking is how identify with regex is if the line ends with vbCrLf without ; to replace the vbCrLf with "" so that the output line becomes

Wyoming is a State;vbCrLf

[dday9]

If you do not want to use regular expressions:

Private Shared Function FormatText(value As String) As String
    Dim lines = value.Split(Environment.NewLine, StringSplitOptions.None)
    Dim formattedText = New StringBuilder()
    For Each line As String In lines
        If (line.EndsWith(";")) Then
            formattedText.AppendLine(line)
        Else
            formattedText.Append($"{line} ")
        End If
    Next
    Return formattedText.ToString()
End Function

If you wanted to use regular expressions:

Private Shared Function FormatText(value As String) As String
    Dim pattern = "(?<!;)\r?\n"
    Dim replacement = " "
    Dim result = Regex.Replace(value, pattern, replacement)
    Return result
End Function

[wqweto]

The line is (for example):

WyomingvbCrLf
is a State;vbCrLf

what I'm asking is how identify with regex is if the line ends with vbCrLf without ; to replace the vbCrLf with "" so that the output line becomes

Wyoming is a State;vbCrLf

So is "(?<!;)(\r?\n)" not working?

I did some testing here: https://regexr.com/84es1



Seems to work.

cheers,
</wqw>

[dday9]

So is "(?<!;)(\r?\n)" not working?

I don't know why, but I didn't see your other post, but I used the same RegEx as you did. I'm curious if it isn't exactly what the OP needs.

[Paulo Lib]

So is "(?<!(\r?\n)" not working?

I did some testing here: https://regexr.com/84es1



Seems to work.

cheers,
</wqw>

Hi.

Thank you for the help.

Your approach didn't work with me either.

It replaced all the vbCrLf with or without ; right behind the vbCrLf.

[.paul.]

Try this...

Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
    Dim s As String = "Wyoming" & vbCrLf & "is a State;" & vbCrLf & "line 2"
    Dim pattern As String = "(?<!;)\r?\n"
    Dim replacement As String = " "
    Dim result As String = Regex.Replace(s, pattern, replacement)
    MsgBox(s)
    MsgBox(result)
End Sub

Edit: Don't forget...

Imports System.Text.RegularExpressions

[wqweto]

Hi.

Thank you for the help.

Your approach didn't work with me either.

It replaced all the vbCrLf with or without ; right behind the vbCrLf.

Show your code which does not work. The regex above is correct and works ok in .Net dialect too.

There must be something else we are missing here.

cheers,
</wqw>

[.paul.]

Don’t forget, \n\r is not equal to \r\n
The correct sequence of characters is \r\n i.e. crlf
The Regex is an exact pattern matcher, in its current form it’ll match \r\n not following ; The \r is optional, but that wouldn’t work properly if your text contains \n\r or ;\n\r

[wqweto]

Btw, the title of the thread is "Regex for ;\r\n" so it's safe to assume that OP must be aware the correct sequence is \r then \n and that the mentioned \n\r is wrong and not recognized as line ending by any standard.

cheers,
</wqw>

[Paulo Lib]

Thank you for your help.

the situation is now soved.