How can you strip non-ASCII characters from a string? (in C#)
14 Answers
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.
If you want not to strip, but to actually convert latin accented to non-accented characters, take a look at this question: How do I translate 8bit characters into 7bit characters? (i.e. Ü to U)
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.
I came here looking for a solution for extended ascii characters, but couldnt find it. The closest I found is bzlm's solution. But that works only for ASCII Code upto 127(obviously you can replace the encoding type in his code, but i think it was a bit complex to understand. Hence, sharing this version). Here's a solution that works for extended ASCII codes i.e. upto 255 which is the ISO 8859-1
It finds and strips out non-ascii characters(greater than 255)
Dim str1 as String= "â, ??î or ôu� n☁i✑++$-♓!‼⁉4⃣od;/⏬'®;☕:☝)///1!@#"
Dim extendedAscii As Encoding = Encoding.GetEncoding("ISO-8859-1",
New EncoderReplacementFallback(String.empty),
New DecoderReplacementFallback())
Dim extendedAsciiBytes() As Byte = extendedAscii.GetBytes(str1)
Dim str2 As String = extendedAscii.GetString(extendedAsciiBytes)
console.WriteLine(str2)
'Output : â, ??î or ôu ni++$-!‼⁉4od;/';:)///1!@#$%^yz:
Here's a working fiddle for the code
Replace the encoding as per the requirement, rest should remain the same.
public string ReturnCleanASCII(string s)
{
StringBuilder sb = new StringBuilder(s.Length);
foreach (char c in s)
{
if ((int)c > 127) // you probably don't want 127 either
continue;
if ((int)c < 32) // I bet you don't want control characters
continue;
if (c == '%')
continue;
if (c == '?')
continue;
sb.Append(c);
}
return sb.ToString();
}
If you want a string with only ISO-8859-1 characters and excluding characters which are not standard, you should use this expression :
var result = Regex.Replace(value, @"[^\u0020-\u007E\u00A0-\u00FF]+", string.Empty);
Note : Using Encoding.GetEncoding("ISO-8859-1") method will not do the job because undefined characters are not excluded.
Wikipedia ISO-8859-1 code page for more details.
Necromancing.
Also, the method by bzlm can be used to remove characters that are not in an arbitrary charset, not just ASCII:
// https://en.wikipedia.org/wiki/Code_page#EBCDIC-based_code_pages
// https://en.wikipedia.org/wiki/Windows_code_page#East_Asian_multi-byte_code_pages
// https://en.wikipedia.org/wiki/Chinese_character_encoding
System.Text.Encoding encRemoveAllBut = System.Text.Encoding.ASCII;
encRemoveAllBut = System.Text.Encoding.GetEncoding(System.Globalization.CultureInfo.InstalledUICulture.TextInfo.ANSICodePage); // System-encoding
encRemoveAllBut = System.Text.Encoding.GetEncoding(1252); // Western European (iso-8859-1)
encRemoveAllBut = System.Text.Encoding.GetEncoding(1251); // Windows-1251/KOI8-R
encRemoveAllBut = System.Text.Encoding.GetEncoding("ISO-8859-5"); // used by less than 0.1% of websites
encRemoveAllBut = System.Text.Encoding.GetEncoding(37); // IBM EBCDIC US-Canada
encRemoveAllBut = System.Text.Encoding.GetEncoding(500); // IBM EBCDIC Latin 1
encRemoveAllBut = System.Text.Encoding.GetEncoding(936); // Chinese Simplified
encRemoveAllBut = System.Text.Encoding.GetEncoding(950); // Chinese Traditional
encRemoveAllBut = System.Text.Encoding.ASCII; // putting ASCII again, as to answer the question
// https://stackoverflow.com/questions/123336/how-can-you-strip-non-ascii-characters-from-a-string-in-c
string inputString = "RäksmörПривет, мирgås";
string asAscii = encRemoveAllBut.GetString(
System.Text.Encoding.Convert(
System.Text.Encoding.UTF8,
System.Text.Encoding.GetEncoding(
encRemoveAllBut.CodePage,
new System.Text.EncoderReplacementFallback(string.Empty),
new System.Text.DecoderExceptionFallback()
),
System.Text.Encoding.UTF8.GetBytes(inputString)
)
);
System.Console.WriteLine(asAscii);
AND for those that just want to remote the accents:
(caution, because Normalize != Latinize != Romanize)
// string str = Latinize("(æøå âôû?aè");
public static string Latinize(string stIn)
{
// Special treatment for German Umlauts
stIn = stIn.Replace("ä", "ae");
stIn = stIn.Replace("ö", "oe");
stIn = stIn.Replace("ü", "ue");
stIn = stIn.Replace("Ä", "Ae");
stIn = stIn.Replace("Ö", "Oe");
stIn = stIn.Replace("Ü", "Ue");
// End special treatment for German Umlauts
string stFormD = stIn.Normalize(System.Text.NormalizationForm.FormD);
System.Text.StringBuilder sb = new System.Text.StringBuilder();
for (int ich = 0; ich < stFormD.Length; ich++)
{
System.Globalization.UnicodeCategory uc = System.Globalization.CharUnicodeInfo.GetUnicodeCategory(stFormD[ich]);
if (uc != System.Globalization.UnicodeCategory.NonSpacingMark)
{
sb.Append(stFormD[ich]);
} // End if (uc != System.Globalization.UnicodeCategory.NonSpacingMark)
} // Next ich
//return (sb.ToString().Normalize(System.Text.NormalizationForm.FormC));
return (sb.ToString().Normalize(System.Text.NormalizationForm.FormKC));
} // End Function Latinize
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