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IsDigit Method (String, Int32)
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Char.IsDigit Method (String, Int32)

Indicates whether the character at the specified position in a specified string is categorized as a decimal digit.

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

public static bool IsDigit(
	string s,
	int index
)

Parameters

s
Type: System.String

A string.

index
Type: System.Int32

The position of the character to evaluate in s.

Return Value

Type: System.Boolean
true if the character at position index in s is a decimal digit; otherwise, false.

ExceptionCondition
ArgumentNullException

s is null.

ArgumentOutOfRangeException

index is less than zero or greater than the last position in s.

This method determines whether a Char is a radix-10 digit. This contrasts with IsNumber, which determines whether a Char is of any numeric Unicode category. Numbers include characters such as fractions, subscripts, superscripts, Roman numerals, currency numerators, encircled numbers, and script-specific digits.

Character positions in a string are indexed starting from zero.

Valid digits are members of the UnicodeCategory.DecimalDigitNumber category.

The following code example demonstrates IsDigit.

using System;

public class IsDigitSample {
	public static void Main() {
		char ch = '8';

		Console.WriteLine(Char.IsDigit(ch));					// Output: "True"
		Console.WriteLine(Char.IsDigit("sample string", 7));	// 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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