CharUnicodeInfo.GetUnicodeCategory Method

Definition

Namespace:

System.Globalization

Assemblies:

netstandard.dll, System.Runtime.dll

Gets the Unicode category of a Unicode character.

Overloads

GetUnicodeCategory(Char)	Gets the Unicode category of the specified character.
GetUnicodeCategory(Int32)	Gets the Unicode category of the specified character.
GetUnicodeCategory(String, Int32)	Gets the Unicode category of the character at the specified index of the specified string.

GetUnicodeCategory(Char)

Source:

CharUnicodeInfo.cs

Gets the Unicode category of the specified character.

C#

public static System.Globalization.UnicodeCategory GetUnicodeCategory(char ch);

Parameters

ch

Char

The Unicode character for which to get the Unicode category.

Returns

UnicodeCategory

A UnicodeCategory value indicating the category of the specified character.

Examples

The following code example shows the values returned by each method for different types of characters.

C#

using System;
using System.Globalization;

public class SamplesCharUnicodeInfo  {

   public static void Main()  {

      Console.WriteLine( "                                        c  Num   Dig   Dec   UnicodeCategory" );

      Console.Write( "U+0061 LATIN SMALL LETTER A            " );
      PrintProperties( 'a' );

      Console.Write( "U+0393 GREEK CAPITAL LETTER GAMMA      " );
      PrintProperties( '\u0393' );

      Console.Write( "U+0039 DIGIT NINE                      " );
      PrintProperties( '9' );

      Console.Write( "U+00B2 SUPERSCRIPT TWO                 " );
      PrintProperties( '\u00B2' );

      Console.Write( "U+00BC VULGAR FRACTION ONE QUARTER     " );
      PrintProperties( '\u00BC' );

      Console.Write( "U+0BEF TAMIL DIGIT NINE                " );
      PrintProperties( '\u0BEF' );

      Console.Write( "U+0BF0 TAMIL NUMBER TEN                " );
      PrintProperties( '\u0BF0' );

      Console.Write( "U+0F33 TIBETAN DIGIT HALF ZERO         " );
      PrintProperties( '\u0F33' );

      Console.Write( "U+2788 CIRCLED SANS-SERIF DIGIT NINE   " );
      PrintProperties( '\u2788' );
   }

   public static void PrintProperties( char c )  {
      Console.Write( " {0,-3}", c );
      Console.Write( " {0,-5}", CharUnicodeInfo.GetNumericValue( c ) );
      Console.Write( " {0,-5}", CharUnicodeInfo.GetDigitValue( c ) );
      Console.Write( " {0,-5}", CharUnicodeInfo.GetDecimalDigitValue( c ) );
      Console.WriteLine( "{0}", CharUnicodeInfo.GetUnicodeCategory( c ) );
   }
}


/*
This code produces the following output.  Some characters might not display at the console.

                                        c  Num   Dig   Dec   UnicodeCategory
U+0061 LATIN SMALL LETTER A             a   -1    -1    -1   LowercaseLetter
U+0393 GREEK CAPITAL LETTER GAMMA       Γ   -1    -1    -1   UppercaseLetter
U+0039 DIGIT NINE                       9   9     9     9    DecimalDigitNumber
U+00B2 SUPERSCRIPT TWO                  ²   2     2     -1   OtherNumber
U+00BC VULGAR FRACTION ONE QUARTER      ¼   0.25  -1    -1   OtherNumber
U+0BEF TAMIL DIGIT NINE                 ௯   9     9     9    DecimalDigitNumber
U+0BF0 TAMIL NUMBER TEN                 ௰   10    -1    -1   OtherNumber
U+0F33 TIBETAN DIGIT HALF ZERO          ༳   -0.5  -1    -1   OtherNumber
U+2788 CIRCLED SANS-SERIF DIGIT NINE    ➈   9     9     -1   OtherNumber

*/

Remarks

The Unicode characters are divided into categories. A character's category is one of its properties. For example, a character might be an uppercase letter, a lowercase letter, a decimal digit number, a letter number, a connector punctuation, a math symbol, or a currency symbol. The UnicodeCategory class returns the category of a Unicode character. For more information on Unicode characters, see the Unicode Standard.

The GetUnicodeCategory method assumes that ch corresponds to a single linguistic character and returns its category. This means that, for surrogate pairs, it returns UnicodeCategory.Surrogate instead of the category to which the surrogate belongs. For example, the Ugaritic alphabet occupies code points U+10380 to U+1039F. The following example uses the ConvertFromUtf32 method to instantiate a string that represents UGARITIC LETTER ALPA (U+10380), which is the first letter of the Ugaritic alphabet. As the output from the example shows, the IsNumber(Char) method returns false if it is passed either the high surrogate or the low surrogate of this character.

C#

int utf32 = 0x10380;       // UGARITIC LETTER ALPA
string surrogate = Char.ConvertFromUtf32(utf32);
foreach (var ch in surrogate)
    Console.WriteLine($"U+{(ushort)ch:X4}: {System.Globalization.CharUnicodeInfo.GetUnicodeCategory(ch):G}");
// The example displays the following output:
//       U+D800: Surrogate
//       U+DF80: Surrogate

Note that CharUnicodeInfo.GetUnicodeCategory does not always return the same UnicodeCategory value as the Char.GetUnicodeCategory method when passed a particular character as a parameter. The CharUnicodeInfo.GetUnicodeCategory method is designed to reflect the current version of the Unicode standard. In contrast, although the Char.GetUnicodeCategory method usually reflects the current version of the Unicode standard, it might return a character's category based on a previous version of the standard, or it might return a category that differs from the current standard to preserve backward compatibility.

See also

• UnicodeCategory

GetUnicodeCategory(Int32)

Source:

CharUnicodeInfo.cs

Gets the Unicode category of the specified character.

C#

public static System.Globalization.UnicodeCategory GetUnicodeCategory(int codePoint);

Parameters

codePoint

Int32

A number representing the 32-bit code point value of the Unicode character.

Returns

UnicodeCategory

A UnicodeCategory value indicating the category of the specified character.

GetUnicodeCategory(String, Int32)

Source:

CharUnicodeInfo.cs

Gets the Unicode category of the character at the specified index of the specified string.

C#

public static System.Globalization.UnicodeCategory GetUnicodeCategory(string s, int index);

Parameters

s

String

The String containing the Unicode character for which to get the Unicode category.

index

Int32

The index of the Unicode character for which to get the Unicode category.

Returns

UnicodeCategory

A UnicodeCategory value indicating the category of the character at the specified index of the specified string.

Exceptions

ArgumentNullException

s is null.

ArgumentOutOfRangeException

index is outside the range of valid indexes in s.

Examples

The following code example shows the values returned by each method for different types of characters.

C#

using System;
using System.Globalization;

public class SamplesCharUnicodeInfo  {

   public static void Main()  {

      // The String to get information for.
      String s = "a9\u0393\u00B2\u00BC\u0BEF\u0BF0\u2788";
      Console.WriteLine( "String: {0}", s );

      // Print the values for each of the characters in the string.
      Console.WriteLine( "index c  Num   Dig   Dec   UnicodeCategory" );
      for ( int i = 0; i < s.Length; i++ )  {
         Console.Write( "{0,-5} {1,-3}", i, s[i] );
         Console.Write( " {0,-5}", CharUnicodeInfo.GetNumericValue( s, i ) );
         Console.Write( " {0,-5}", CharUnicodeInfo.GetDigitValue( s, i ) );
         Console.Write( " {0,-5}", CharUnicodeInfo.GetDecimalDigitValue( s, i ) );
         Console.WriteLine( "{0}", CharUnicodeInfo.GetUnicodeCategory( s, i ) );
      }
   }
}


/*
This code produces the following output.  Some characters might not display at the console.

String: a9Γ²¼௯௰➈
index c  Num   Dig   Dec   UnicodeCategory
0     a   -1    -1    -1   LowercaseLetter
1     9   9     9     9    DecimalDigitNumber
2     Γ   -1    -1    -1   UppercaseLetter
3     ²   2     2     -1   OtherNumber
4     ¼   0.25  -1    -1   OtherNumber
5     ௯   9     9     9    DecimalDigitNumber
6     ௰   10    -1    -1   OtherNumber
7     ➈   9     9     -1   OtherNumber

*/

Remarks

The Unicode characters are divided into categories. A character's category is one of its properties. For example, a character might be an uppercase letter, a lowercase letter, a decimal digit number, a letter number, a connector punctuation, a math symbol, or a currency symbol. The UnicodeCategory class returns the category of a Unicode character. For more information on Unicode characters, see the Unicode Standard.

If the Char object at position index is the first character of a valid surrogate pair, the GetUnicodeCategory(String, Int32) method returns the Unicode category of the surrogate pair instead of returning UnicodeCategory.Surrogate. For example, the Ugaritic alphabet occupies code points U+10380 to U+1039F. The following example uses the ConvertFromUtf32 method to instantiate a string that represents UGARITIC LETTER ALPA (U+10380), which is the first letter of the Ugaritic alphabet. As the output from the example shows, the GetUnicodeCategory(String, Int32) method returns UnicodeCategory.OtherLetter if it is passed the high surrogate of this character, which indicates that it considers the surrogate pair. However, if it is passed the low surrogate, it considers only the low surrogate in isolation and returns UnicodeCategory.Surrogate.

C#

int utf32 = 0x10380;       // UGARITIC LETTER ALPA
string surrogate = Char.ConvertFromUtf32(utf32);
for (int ctr = 0; ctr < surrogate.Length; ctr++)
    Console.WriteLine($"U+{(ushort)surrogate[ctr]:X4}: {System.Globalization.CharUnicodeInfo.GetUnicodeCategory(surrogate, ctr):G}");
// The example displays the following output:
//       U+D800: OtherLetter
//       U+DF80: Surrogate

Note that CharUnicodeInfo.GetUnicodeCategory method does not always return the same UnicodeCategory value as the Char.GetUnicodeCategory method when passed a particular character as a parameter. The CharUnicodeInfo.GetUnicodeCategory method is designed to reflect the current version of the Unicode standard. In contrast, although the Char.GetUnicodeCategory method usually reflects the current version of the Unicode standard, it might return a character's category based on a previous version of the standard, or it might return a category that differs from the current standard to preserve backward compatibility.

See also

• UnicodeCategory