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C# / .NET - check if string contains only letters
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In this article, we would like to show you how to check if string contains only letters in C#.
Quick solution:
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string text1 = "ABC";2
string text2 = "ABC123";3
4
string regex = "^[a-zA-Z]+$";5
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bool result1 = Regex.IsMatch(text1, regex); // True7
bool result2 = Regex.IsMatch(text2, regex); // Falseor:
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string text1 = "ABC";2
string text2 = "ABC123";3
4
bool result1 = text1.All(Char.IsLetter); // True5
bool result2 = text2.All(Char.IsLetter); // False
In this example, we use a regular expression (regex) with IsMatch() to check if the strings contain only letters.
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using System;2
using System.Text.RegularExpressions;3
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public class Program5
{6
public static void Main()7
{8
string text1 = "ABC";9
string text2 = "ABC123";10
11
string regex = "^[a-zA-Z]+$";12
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bool result1 = Regex.IsMatch(text1, regex);14
bool result2 = Regex.IsMatch(text2, regex);15
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Console.WriteLine(result1); // True17
Console.WriteLine(result2); // False18
}19
}Output:
xxxxxxxxxx1
True2
FalseIn this example, we use All() from System.Linq with IsLetter() method to check if all characters in strings are letters.
xxxxxxxxxx1
using System;2
using System.Linq;3
4
public class Program5
{6
public static void Main()7
{8
string text1 = "ABC";9
string text2 = "ABC123";10
11
bool result1 = text1.All(Char.IsLetter);12
bool result2 = text2.All(Char.IsLetter);13
14
Console.WriteLine(result1); // True15
Console.WriteLine(result2); // False16
}17
}Output:
xxxxxxxxxx1
True2
False