Finding the last index of an array

Question

How do you retrieve the last element of an array in C#?

Answer 1

LINQ provides Last():

csharp> int[] nums = {1,2,3,4,5};
csharp> nums.Last();              
5

This is handy when you don't want to make a variable unnecessarily.

string lastName = "Abraham Lincoln".Split().Last();

Answer 2

With C# 8:

int[] array = { 1, 3, 5 };
var lastItem = array[^1]; // 5

Answer 3

To compute the index of the last item:

int index = array.Length - 1;

Will get you -1 if the array is empty - you should treat it as a special case.

To access the last index:

array[array.Length - 1] = ...

or

... = array[array.Length - 1]

will cause an exception if the array is actually empty (Length is 0).

Answer 4

The following will return NULL if the array is empty, else the last element.

var item = (arr.Length == 0) ? null : arr[arr.Length - 1]

Answer 5

say your array is called arr

do

arr[arr.Length - 1]

Answer 6

Use Array.GetUpperBound(0). Array.Length contains the number of items in the array, so reading Length -1 only works on the assumption that the array is zero based.