Getting rid of Extended ASCII characters in a string

Question

I have a string that has extended ASCII char ÿ in it and I am trying to delete it. How do I find it in a string and delete it from a string like this: 1ÿ1ÿ0ÿÿÿ ?

The byte array, buffer = { 49, 0, 255, 255, 49, 0, 255, 255, 48, 0, 255, 255, 255, 255 }

I am using C# and the string was formed from a byte array like so: temp.Add(System.Text.Encoding.ASCII.GetString(buffer));

Then, the first item in temp is "1\\0??1\\0??0\\0????"

I would like to remove the non-ASCII values from the string, or better yet the buffer.

Answer 1

To work with all non-ASCII characters in a string:

Where '?' is your replacement character.

var clean = new string("1ÿ1ÿ0ÿÿÿ".Select(c => c > 127 ? '?' : c).ToArray());

or

var clean = new string("1ÿ1ÿ0ÿÿÿ".Where(c => c <= 127).ToArray());

If you want to remove characters.

Update

In response to your update you can remove non-ascii characters from your buffer to create a string as follows:

string clean = new string(buffer.Where(b => b <= 127).Select(b => (char)b).ToArray());

Answer 2

更换有什么问题。

temp.replace("ÿ","");

Answer 3

To remove the characters from the buffer before creating the string:

byte[] buffer = new byte[] { 49, 0, 255, 255, 49, 0, 255, 255, 48, 0, 255, 255, 255, 255 }
var cleanBuffer = buffer.Where((b) => b < 128).ToArray();
string temp = Encoding.ASCII.GetString(cleanBuffer);

If you try to convert it to a string and then remove the offending characters, you can't tell the difference between a legitimate ? character and one that was placed there because conversion failed. That is, if your buffer contained:

{ 63, 63, 49, 0, 255, 255, 49, 0, 255, 255, 48, 0, 255, 255, 255, 255 }

Then the resulting string would start with ??1\\0?? . The first two question marks are legitimate, but the last two are the result of conversion failure.

Answer 4

Loop over the entire string and add only those characters that are ASCII.

    ' http://stackoverflow.com/questions/123336/how-can-you-strip-non-ascii-characters-from-a-string-in-c
    Public Shared Function GetAsciiString(ByVal strInputString As String) As String
        Dim strASCII As String = System.Text.Encoding.ASCII.GetString( _
                                                                        System.Text.Encoding.Convert(System.Text.Encoding.UTF8, _
                                                                                                        System.Text.Encoding.GetEncoding(System.Text.Encoding.ASCII.EncodingName, _
                                                                                                        New System.Text.EncoderReplacementFallback(String.Empty), _
                                                                                                        New System.Text.DecoderExceptionFallback()), _
                                                                                                        System.Text.Encoding.UTF8.GetBytes(strInputString) _
                                                                                                    ) _
                                                                    )

        Return strASCII
    End Function


    Public Shared Function IsAscii(ByVal strInputString As String) As Boolean
        'Dim strInputString As String = "Räksmörgås"
        If (GetAsciiString(strInputString) = strInputString) Then
            Return True
        End If

        Return False
    End Function

Edit: Here C#:

// http://stackoverflow.com/questions/123336/how-can-you-strip-non-ascii-characters-from-a-string-in-c
public static string GetAsciiString(string strInputString)
{
    string strASCII = System.Text.Encoding.ASCII.GetString(System.Text.Encoding.Convert(System.Text.Encoding.UTF8, System.Text.Encoding.GetEncoding(System.Text.Encoding.ASCII.EncodingName, new System.Text.EncoderReplacementFallback(string.Empty), new System.Text.DecoderExceptionFallback()), System.Text.Encoding.UTF8.GetBytes(strInputString)));

    return strASCII;
}


public static bool IsAscii(string strInputString)
{
    //Dim strInputString As String = "Räksmörgås"
    if ((GetAsciiString(strInputString) == strInputString)) {
        return true;
    }

    return false;
}