Updated: October 2008
Indicates whether the character at the specified position in a specified string is categorized as a number.
Namespace:
System
Assembly:
mscorlib (in mscorlib.dll)
Visual Basic (Declaration)
Public Shared Function IsNumber ( _
s As String, _
index As Integer _
) As Boolean
Dim s As String
Dim index As Integer
Dim returnValue As Boolean
returnValue = Char.IsNumber(s, index)
public static bool IsNumber(
string s,
int index
)
public:
static bool IsNumber(
String^ s,
int index
)
public static function IsNumber(
s : String,
index : int
) : boolean
Return Value
Type:
System..::.Boolean
true if the character at position index in s is a number; otherwise, false.
This method determines if a Char is of any numeric Unicode category. In addition to digits, numbers include characters, fractions, subscripts, superscripts, Roman numerals, currency numerators, and encircled numbers. This method contrasts with the IsDigit method, which determines if a Char is a radix-10 digit.
Character positions in a string are indexed starting from zero.
Valid numbers are members of the UnicodeCategory..::.DecimalDigitNumber, UnicodeCategory..::.LetterNumber, or UnicodeCategory..::.OtherNumber categories.
The following code example demonstrates IsNumber.
Imports System
Module IsNumberSample
Sub Main()
Dim str As String
str = "non-numeric"
Console.WriteLine(Char.IsNumber("8"c)) ' Output: "True"
Console.WriteLine(Char.IsNumber(str, 3)) ' Output: "False"
End Sub
End Module
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"
}
}
using namespace System;
int main()
{
String^ str = "non-numeric";
Console::WriteLine( Char::IsNumber( '8' ) ); // Output: "True"
Console::WriteLine( Char::IsNumber( str, 3 ) ); // Output: "False"
}
Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune
The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
.NET Framework
Supported in: 3.5, 3.0, 2.0, 1.1, 1.0
.NET Compact Framework
Supported in: 3.5, 2.0, 1.0
XNA Framework
Supported in: 3.0, 2.0, 1.0
Reference
Date | History | Reason |
|---|
October 2008
| Added detail about the difference between the IsDigit and IsNumber methods. |
Customer feedback.
|