Efficiently create reverse copy of a string in C#

This article illustrates the different techniques to efficiently create a reverse copy of a string in C#.

1. Using `Array.Reverse()` method

We can use Array.reverse() to create a reverse copy of a string in C#. The idea is to convert the given string into a character array using the String.toCharArray() method, and reverse the array using the Array.Reverse() method. Then, convert the character array back into a string using the String constructor and return it. The following program demonstrates it:

using System;

public static class StringExtensions

{

public static string Reverse(this string str)

{

char[] chars = str.ToCharArray();

Array.Reverse(chars);

return new string(chars);

}

public class Example

{

public static void Main()

{

string str = "Hello World";

string rev = str.Reverse();

Console.WriteLine(rev);

}

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2. Using `String.Create()` method

Starting with .NET 6, you can use the String.Create() method to reverse a string. It creates a new string with a specific length and initializes it after creation by using the specified callback. The following example demonstrates its usage:

using System;

using System.Linq;

public static class StringExtensions

{

public static string Reverse(this string str)

{

return string.Create<string>(str.Length, str, (c, s) =>

{

s.AsSpan().CopyTo(c);

c.Reverse();

});

}

public class Example

{

public static void Main()

{

string str = "Hello World";

string rev = str.Reverse();

Console.WriteLine(rev);

}

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That’s all about efficiently creating a reverse copy of a string in C#.

Efficiently create reverse copy of a string in C#

1. Using Array.Reverse() method

2. Using String.Create() method

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1. Using `Array.Reverse()` method

2. Using `String.Create()` method