System.Linq.Enumerable.Reverse Method

                public static IEnumerable<TSource> Reverse<TSource>(this IEnumerable<TSource> source)
            

Returns a reversed enumerator over the collection.

Parameters

source The sequence to reverse.

Returns

IEnumerable<TSource> An System.Collections.Generic.IEnumerable<TSource> that contains elements in reverse order.

Remarks

If the collection is a List<T>, Array, or ICollection<T>, Reverse is more efficient because it can use the underlying storage to reverse the elements.

If the collection is an IEnumerable<T> that does not implement ICollection<T>, the method iterates through the collection to reverse the elements.

This method defers execution by default. IEnumerable<T> deferred execution.

Exceptions

System.ArgumentNullException source is null.

Examples

Example 1: Reversing a list of integers

This example demonstrates how to reverse a list of integers.

                    using System;
using System.Collections.Generic;
using System.Linq;

public class Example
{
    public static void Main(string[] args)
    {
        List<int> numbers = new List<int> { 1, 2, 3, 4, 5 };

        Console.WriteLine("Original list:");
        foreach (int number in numbers)
        {
            Console.Write(number + " ");
        }
        Console.WriteLine();

        IEnumerable<int> reversedNumbers = numbers.Reverse();

        Console.WriteLine("Reversed list:");
        foreach (int number in reversedNumbers)
        {
            Console.Write(number + " ");
        }
        Console.WriteLine();
    }
}
                

                    // Output:
// Original list:
// 1 2 3 4 5
// Reversed list:
// 5 4 3 2 1
                

Example 2: Reversing a string

This example shows how to reverse a string by treating it as a sequence of characters.

                    using System;
using System.Collections.Generic;
using System.Linq;

public class Example
{
    public static void Main(string[] args)
    {
        string originalString = "Hello World";

        Console.WriteLine("Original string: " + originalString);

        string reversedString = new string(originalString.Reverse().ToArray());

        Console.WriteLine("Reversed string: " + reversedString);
    }
}
                

                    // Output:
// Original string: Hello World
// Reversed string: dlroW olleH
                