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IsNumber Method (Char)
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Char.IsNumber Method (Char)

Indicates whether the specified Unicode character is categorized as a number.

Namespace:  System
Assembly:  mscorlib (in mscorlib.dll)

public static bool IsNumber(
	char c
)

Parameters

c
Type: System.Char

The Unicode character to evaluate.

Return Value

Type: System.Boolean
true if c is a number; otherwise, false.

This method determines whether a Char is of any numeric Unicode category. In addition to including digits, numbers include characters, fractions, subscripts, superscripts, Roman numerals, currency numerators, and encircled numbers. This method contrasts with the IsDigit method, which determines whether a Char is a radix-10 digit.

Valid numbers are members of the UnicodeCategory.DecimalDigitNumber, UnicodeCategory.LetterNumber, or UnicodeCategory.OtherNumber category.

The IsNumber(Char) method assumes that c corresponds to a single linguistic character and checks whether that character represents a number. 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 IsNumber(Char) method returns false if it is passed either a high surrogate or a low surrogate of this character.

int utf32 = 0x10107;      // AEGEAN NUMBER ONE 
string surrogate = Char.ConvertFromUtf32(utf32);
foreach (var ch in surrogate)
   Console.WriteLine("U+{0:X4}: {1}", Convert.ToUInt16(ch), 
                                    Char.IsNumber(ch));

// The example displays the following output: 
//       U+D800: False 
//       U+DD07: False       

The following example demonstrates IsNumber.

using System;

public class IsNumberSample {
	public static void Main() {
		string str = "non-numeric";

		Console.WriteLine(Char.IsNumber('8'));		// Output: "True"
		Console.WriteLine(Char.IsNumber(str, 3));	// Output: "False"
	}
}

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0, 1.1

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

XNA Framework

Supported in: 3.0, 2.0, 1.0

.NET for Windows Phone apps

Supported in: Windows Phone 8.1, Windows Phone Silverlight 8.1, Windows Phone Silverlight 8

Portable Class Library

Supported in: Portable Class Library
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