Array.LastIndexOf() Method in C#


The Array.LastIndexOf() method in C# is used to search for the specified object and returns the index of the last occurrence within the entire one-dimensional Array.

Syntax

public static int LastIndexOf (Array arr, object val);

Above, arr is the one-dimensional Array to search, whereas val is the object to locate in arr.

Example

 Live Demo

using System;
public class Demo {
   public static void Main() {
      string[] strArr = {"John", "Tim", "Fedric", "Gary", "Harry", "Damien", "David", "Harry"};
      Array.Sort(strArr);
      Console.WriteLine("Array elements...");
      foreach(string s in strArr) {
         Console.WriteLine(s);
      }
      Console.Write("Element Gary is at index = " + Array.BinarySearch(strArr, "Gary"));
      Console.Write("\nElement Tom is at index = " + Array.BinarySearch(strArr, "Tom"));
      Console.Write("\nLast index of element Harry = " + Array.LastIndexOf(strArr, "Harry"));
   }
}

Output

Array elements...
Damien
David
Fedric
Gary
Harry
Harry
John
Tim
Element Gary is at index = 3
Element Tom is at index = -9
Last index of element Harry = 5

Example

 Live Demo

using System;
public class Demo {
   public static void Main() {
      int[] intArr = {5, 10, 15, 20, 15, 25, 30};
      Array.Sort(intArr);
      Console.WriteLine("Array elements...");
      foreach(int i in intArr) {
         Console.WriteLine(i);
      }
      Console.Write("Element 25 is at index = " + Array.BinarySearch(intArr, 20));
      Console.Write("\nLast index of element 15 = " + Array.LastIndexOf(intArr, 15));
      Console.Write("\nLast index of element 50 = " + Array.LastIndexOf(intArr, 50));
   }
}

Output

Array elements...
5
10
15
15
20
25
30
Element 25 is at index = 4
Last index of element 15 = 3
Last index of element 50 = -1
raja
Published on 03-Dec-2019 10:29:29
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