Index operator ^1
The index operator is used to reach the last positions of an array or list.
before
List<int> arr = [0, 1, 2, 3, 4, 5];
if(arr[arr.Count-1] == 5)
Console.WriteLine("match!"); // prints
same but using index operator
List<int> arr = [0, 1, 2, 3, 4, 5];
if(arr[^1] == 5)
Console.WriteLine("match!"); // prints
we can use it to reach any position starting from the back
List<int> arr = [0, 1, 2, 3, 4, 5];
if(arr[^2] == 4)
Console.WriteLine("match!"); // prints
Range operator ..
The range operator is used to make a slice of a collection
- start of the range is inclusive
- end of the range is exclusive
sample .. means range of all elements
List<int> arr = [0, 1, 2, 3, 4, 5];
var subList = arr[..];
foreach(var item in subList)
Console.Write(item); // 0 1 2 3 4 5
whole range
List<int> arr = [0, 1, 2, 3, 4, 5];
var subList = arr[1..3];
foreach(var item in subList)
Console.Write(item); // 1 2
we may omit the start or the end
List<int> arr = [0, 1, 2, 3, 4, 5];
var subList = arr[..3];
foreach(var item in subList)
Console.Write(item); // 0 1 2
List<int> arr = [0, 1, 2, 3, 4, 5];
var subList = arr[2..];
foreach(var item in subList)
Console.Write(item); // 2 3 4 5
Mixing index and range operators
Both operators can be mixed to set a limit by the back of the list
List<int> arr = [0, 1, 2, 3, 4, 5];
var subList = arr[1..^1];
foreach(var item in subList)
Console.Write(item); // 1 2 3 4
List<int> arr = [0, 1, 2, 3, 4, 5];
var subList = arr[..^2];
foreach(var item in subList)
Console.Write(item); // 0 1 2 3