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C# / .NET - check if string contains only numbers
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In this article, we would like to show you how to check if string contains only numbers in C#.
Quick solution:
xxxxxxxxxx1
string number = "123";2
string text = "ABC123";3
4
string pattern = "^[0-9]+$"; // regular expression pattern5
// to check if string contains only numbers6
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bool result1 = Regex.IsMatch(number, pattern); // True8
bool result2 = Regex.IsMatch(text, pattern); // Falseor:
xxxxxxxxxx1
string number = "123";2
string text = "A123";3
4
bool result1 = number.All(Char.IsDigit); // True5
bool result2 = text.All(Char.IsDigit); // False
In this example, we use regular expression with specified pattern to check if string contains only numbers.
xxxxxxxxxx1
using System;2
using System.Text.RegularExpressions;3
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public class Program5
{6
public static void Main()7
{8
string number = "123";9
string text = "ABC123";10
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string pattern = "^[0-9]+$"; // regular expression pattern12
// to check if string contains only numbers13
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bool result1 = Regex.IsMatch(number, pattern);15
bool result2 = Regex.IsMatch(text, pattern);16
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Console.WriteLine(result1); // True18
Console.WriteLine(result2); // False19
}20
}Output:
xxxxxxxxxx1
True2
FalseIn this example, we use All() method from System.Linq namespace combined with Char.IsDigit() to check if string contains only numbers.
xxxxxxxxxx1
using System;2
using System.Linq;3
4
public class Program5
{6
public static void Main()7
{8
string number = "123";9
string text = "A123";10
11
bool result1 = number.All(Char.IsDigit);12
bool result2 = text.All(Char.IsDigit);13
14
Console.WriteLine(result1); // True15
Console.WriteLine(result2); // False16
}17
}Output:
xxxxxxxxxx1
True2
False