Reverse C# with Example

Inverts the order of the elements in a sequence. 
If there is no items throws a ArgumentNullException: source is null. 
Example: 
// Create an array. 
int[] array = { 1, 2, 3, 4 }; //Output: 
// Call reverse extension method on the array. //4 
//3 
var reverse = array.Reverse(); 
// Write contents of array to screen. //2 
foreach (int value in reverse) //1 
Console.WriteLine(value); 
Live code example 
Remeber that Reverse() may work diffrent depending on the chain order of your LINQ statements. 
//Create List of chars 
List integerlist = new List() { 1, 2, 3, 4, 5, 6 }; 
//Reversing the list then taking the two first elements 
IEnumerable reverseFirst = integerlist.Reverse().Take(2); 
//Taking 2 elements and then reversing only thos two 
IEnumerable reverseLast = integerlist.Take(2).Reverse(); 
//reverseFirst output: 6, 5 
//reverseLast output: 2, 1 
Live code example 
Reverse() works by buffering everything then walk through it backwards, whitch is not very efficient, but neither is 
OrderBy from that perspective. 
In LINQ-to-Objects, there are buffering operations (Reverse, OrderBy, GroupBy, etc) and non-buffering operations 
(Where, Take, Skip, etc). 
Example: Non-b uff e ri ng Reverse extention 
public static IEnumerable Reverse(this IList list) { 
for (int i = list.Count - 1; i >= 0; i--) 
yield return list[i]; 
} 
Live code example 
This method can encounter problems if u mutate the list while iterating.