How can you strip non-ASCII characters from a string? (in C#)

Question

How can you strip non-ASCII characters from a string? (in C#)

Answer 1

   string s = "søme string";
   s = Regex.Replace(s, @"[^\u0000-\u007F]", "");
   

Answer 2

Here is a pure .NET solution that doesn't use regular expressions:

        string inputString = "Räksmörgås";
        string asAscii = Encoding.ASCII.GetString(
            Encoding.Convert(
                Encoding.UTF8,
                Encoding.GetEncoding(
                    Encoding.ASCII.EncodingName,
                    new EncoderReplacementFallback(string.Empty),
                    new DecoderExceptionFallback()
                    ),
                Encoding.UTF8.GetBytes(inputString)
            )
        );

It may look cumbersome, but it should be intuitive. It uses the .NET ASCII encoding to convert a string. UTF8 is used during the conversion because it can represent any of the original characters. It uses an EncoderReplacementFallback to to convert any non-ASCII character to an empty string.

Answer 3

Inspired by philcruz's Regular Expression solution, I've made a pure LINQ solution

    public static string PureAscii(this string source, char nil = ' ')
    {
        var min = '\u0000';
        var max = '\u007F';
        return source.Select(c => c < min ? nil : c > max ? nil : c).ToText();
    }

    public static string ToText(this IEnumerable<char> source)
    {
        var buffer = new StringBuilder();
        foreach (var c in source)
            buffer.Append(c);
        return buffer.ToString();
    }

This is untested code.