Check if a string starts with a given prefix in C#

This article illustrates the different techniques to check if a string starts with a given prefix in C#.

1. Using `String.StartsWith()` method

The standard solution to determine if a string starts with a given prefix or not is using the String.StartsWith() method. It returns true if the specified string matches the beginning of the string instance; false otherwise.

using System;

public class Example

{

public static void Main()

{

string website = "google.com";

string prefix = "google";

bool result = website.StartsWith(prefix);

Console.WriteLine(result); // True

}

Download Run Code

2. Using `Enumerable.Any()` method

To match a string that starts with any of the given list of prefixes, you can use LINQ’s Enumerable.Any() method. It returns true if any element of the sequence satisfies the specified condition. This is demonstrated below:

using System;

using System.Linq;

public class Example

{

public static void Main()

{

string[] companies = { "google", "microsoft", "youtube" };

string website = "google.com";

bool result = companies.Any(prefix => website.StartsWith(prefix));

Console.WriteLine(result); // True

}

Download Run Code

3. Using `Regex.IsMatch()` method

Another option is to use regular expressions to match a string that starts with any of the given list of prefixes. This can be done using the Regex.IsMatch() method, which returns true if the string matches the given regular expression.

The following code example demonstrates how to use the Regex.IsMatch() method for determining whether a string starts with any of the given strings. Here, ^ matches with the start of the string, and (google|microsoft|youtube) matches the string from the beginning with any of the values separated by |.

using System;

using System.Text.RegularExpressions;

public class Example

{

public static void Main()

{

string website = "google.com";

bool result = Regex.IsMatch(website, "^(google|microsoft|youtube)");

Console.WriteLine(result); // True

}

Download Run Code

That’s all about checking if a string starts with a given prefix in C#.

Check if a string starts with a given prefix in C#

1. Using String.StartsWith() method

2. Using Enumerable.Any() method

3. Using Regex.IsMatch() method

Share this:

1. Using `String.StartsWith()` method

2. Using `Enumerable.Any()` method

3. Using `Regex.IsMatch()` method