CharUnicodeInfo.GetNumericValue Method (Char)
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Updated: December 2010
Gets the numeric value associated with the specified character.
Namespace: System.Globalization
Assembly: mscorlib (in mscorlib.dll)
Syntax
'Declaration
Public Shared Function GetNumericValue ( _
ch As Char _
) As Double
public static double GetNumericValue(
char ch
)
Parameters
- ch
Type: System.Char
The Unicode character for which to get the numeric value.
Return Value
Type: System.Double
The numeric value associated with the specified character.
-or-
-1, if the specified character is not a numeric character.
Remarks
This property applies only to numeric characters, which include fractions, subscripts, superscripts, Roman numerals, currency numerators, encircled numbers, and script-specific digits.
For more information on Unicode characters, see the Unicode Standard.
The GetNumericValue method assumes that ch corresponds to a single linguistic character and checks whether that character can be converted to a decimal digit. However, some numbers in the Unicode standard are represented by two Char objects that form a surrogate pair. For example, the Aegean numbering system consists of code points U+10107 through U+10133. The following example uses the ConvertFromUtf32 method to instantiate a string that represents AEGEAN NUMBER ONE. As the output from the example shows, the GetNumericValue method returns -1 if it is passed either a high surrogate or a low surrogate of this character.
Dim surrogate As String = ChrW(&hD800) + ChrW(&hDD07) ' AEGEAN NUMBER ONE
For Each ch In surrogate
outputBlock.Text += String.Format("U+{0:X4}: {1} ", Convert.ToUInt16(ch),
System.Globalization.CharUnicodeInfo.GetNumericValue(ch)) & vbCrLf
Next
' The example displays the following output:
' U+D800: -1
' U+DD07: -1
string surrogate = "\uD800\uDD07"; // AEGEAN NUMBER ONE
foreach (var ch in surrogate)
outputBlock.Text += String.Format("U+{0:X4}: {1} ", Convert.ToUInt16(ch),
System.Globalization.CharUnicodeInfo.GetNumericValue(ch)) + "\n";
// The example displays the following output:
// U+D800: -1
// U+DD07: -1
Examples
The following code example shows the values returned by each method for different types of characters.
Imports System.Globalization
Public Class Example
Public Shared Sub Demo(ByVal outputBlock As System.Windows.Controls.TextBlock)
outputBlock.Text &= " c Num UnicodeCategory" & vbCrLf
outputBlock.Text &= "U+0061 LATIN SMALL LETTER A "
PrintProperties(outputBlock, "a"c)
outputBlock.Text &= "U+0393 GREEK CAPITAL LETTER GAMMA "
PrintProperties(outputBlock, ChrW(&H393))
outputBlock.Text &= "U+0039 DIGIT NINE "
PrintProperties(outputBlock, "9"c)
outputBlock.Text &= "U+00B2 SUPERSCRIPT TWO "
PrintProperties(outputBlock, ChrW(&HB2))
outputBlock.Text &= "U+00BC VULGAR FRACTION ONE QUARTER "
PrintProperties(outputBlock, ChrW(&HBC))
outputBlock.Text &= "U+0BEF TAMIL DIGIT NINE "
PrintProperties(outputBlock, ChrW(&HBEF))
outputBlock.Text &= "U+0BF0 TAMIL NUMBER TEN "
PrintProperties(outputBlock, ChrW(&HBF0))
outputBlock.Text &= "U+0F33 TIBETAN DIGIT HALF ZERO "
PrintProperties(outputBlock, ChrW(&HF33))
outputBlock.Text &= "U+2788 CIRCLED SANS-SERIF DIGIT NINE "
PrintProperties(outputBlock, ChrW(&H2788))
End Sub
Public Shared Sub PrintProperties(ByVal outputBlock As System.Windows.Controls.TextBlock, ByVal c As Char)
outputBlock.Text += String.Format(" {0,-3}", c)
outputBlock.Text += String.Format(" {0,-5}", CharUnicodeInfo.GetNumericValue(c))
outputBlock.Text += String.Format("{0}", CharUnicodeInfo.GetUnicodeCategory(c)) & vbCrLf
End Sub
End Class
' This example produces the following output.
' U+0061 LATIN SMALL LETTER A a -1 LowercaseLetter
' U+0393 GREEK CAPITAL LETTER GAMMA G -1 UppercaseLetter
' U+0039 DIGIT NINE 9 9 DecimalDigitNumber
' U+00B2 SUPERSCRIPT TWO � 2 OtherNumber
' U+00BC VULGAR FRACTION ONE QUARTER � 0.25 OtherNumber
' U+0BEF TAMIL DIGIT NINE ? 9 DecimalDigitNumber
' U+0BF0 TAMIL NUMBER TEN ? 10 OtherNumber
' U+0F33 TIBETAN DIGIT HALF ZERO ? -0.5 OtherNumber
' U+2788 CIRCLED SANS-SERIF DIGIT NINE ? 9 OtherNumber
using System;
using System.Globalization;
public class Example
{
public static void Demo(System.Windows.Controls.TextBlock outputBlock)
{
outputBlock.Text += " c Num Dig Dec UnicodeCategory" + "\n";
outputBlock.Text += "U+0061 LATIN SMALL LETTER A ";
PrintProperties(outputBlock, 'a');
outputBlock.Text += "U+0393 GREEK CAPITAL LETTER GAMMA ";
PrintProperties(outputBlock, '\u0393');
outputBlock.Text += "U+0039 DIGIT NINE ";
PrintProperties(outputBlock, '9');
outputBlock.Text += "U+00B2 SUPERSCRIPT TWO ";
PrintProperties(outputBlock, '\u00B2');
outputBlock.Text += "U+00BC VULGAR FRACTION ONE QUARTER ";
PrintProperties(outputBlock, '\u00BC');
outputBlock.Text += "U+0BEF TAMIL DIGIT NINE ";
PrintProperties(outputBlock, '\u0BEF');
outputBlock.Text += "U+0BF0 TAMIL NUMBER TEN ";
PrintProperties(outputBlock, '\u0BF0');
outputBlock.Text += "U+0F33 TIBETAN DIGIT HALF ZERO ";
PrintProperties(outputBlock, '\u0F33');
outputBlock.Text += "U+2788 CIRCLED SANS-SERIF DIGIT NINE ";
PrintProperties(outputBlock, '\u2788');
}
public static void PrintProperties(System.Windows.Controls.TextBlock outputBlock, char c)
{
outputBlock.Text += String.Format(" {0,-3}", c);
outputBlock.Text += String.Format(" {0,-5}", CharUnicodeInfo.GetNumericValue(c));
outputBlock.Text += String.Format("{0}", CharUnicodeInfo.GetUnicodeCategory(c)) + "\n";
}
}
/*
This example produces the following output.
U+0061 LATIN SMALL LETTER A a -1 LowercaseLetter
U+0393 GREEK CAPITAL LETTER GAMMA G -1 UppercaseLetter
U+0039 DIGIT NINE 9 9 DecimalDigitNumber
U+00B2 SUPERSCRIPT TWO ² 2 OtherNumber
U+00BC VULGAR FRACTION ONE QUARTER ¼ 0.25 OtherNumber
U+0BEF TAMIL DIGIT NINE ? 9 DecimalDigitNumber
U+0BF0 TAMIL NUMBER TEN ? 10 OtherNumber
U+0F33 TIBETAN DIGIT HALF ZERO ? -0.5 OtherNumber
U+2788 CIRCLED SANS-SERIF DIGIT NINE ? 9 OtherNumber
*/
Version Information
Silverlight
Supported in: 5, 4, 3
Silverlight for Windows Phone
Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0
XNA Framework
Supported in: Xbox 360, Windows Phone OS 7.0
Platforms
For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.
Change History
Date |
History |
Reason |
|---|---|---|
December 2010 |
Added information about how the method handles surrogate pairs. |
Information enhancement. |