Compare performance of Array and ArrayList

Compare performance of Array and ArrayList

In this quick tutorial we will compare execution speed of Array and ArrayList in C#. We know that ArrayList is one type of collection in C# and store object. In practical Array is more faster than ArrayList. In this article we will prove it practically.

Time taken to initialize Array and ArrayList

At first we will see the performance difference between Array and ArrayList in time to initialization.

using System;
using System.Collections.Generic;
using System.Text;
using System.Diagnostics;
using System.Collections;
namespace Client
{
    class Program
    {
        static void Main(string[] args)
        {
            int[] Array = new int[1000];
            ArrayList li = new ArrayList(1000);
            Stopwatch sw = new Stopwatch();
            
            //Process with Array, Initialization
            sw.Start();
            for (int i = 0; i < 1000; i++)
            {
                Array[i] = i;
            }
            sw.Stop();
            Console.WriteLine("Array Takes :- " + sw.ElapsedTicks);
 
            //Process with ArrayList
            sw.Restart();
            for (int i = 0; i < 1000; i++)
            {
                li.Add(i);
            }
            sw.Stop();
            Console.WriteLine("ArrayList Takes :-" + sw.ElapsedTicks);
            Console.ReadLine();
        }
    }
}

Here is sample output.

 We are seeing that Array is nearly three times faster than ArrayLiat. Now, the question is why Array is faster than ArrayList in this scenario. The reason is Boxing and Unboxing.  When we are trying to initialize integer value to ArrayList it’s storing as object type rather than value type. This conversion taking time to initialize value in ArrayList. Whereas in case of Array this does not happen.  When we store value in array it get stored as value type.

Time taken to read Array and ArrayList

check with array.

In this example we will measure only accessing and printing time of data from Array. Here is sample example.

using System;
using System.Linq;
using System.Text;
using System.Diagnostics;
using System.Collections;
namespace Client
{
    class Program
    {
        static void Main(string[] args)
        {
            int[] Array = new int[1000];
            Stopwatch sw = new Stopwatch();
            
            //Process with Array, Initialization
            for (int i = 0; i < 1000; i++)
            {
                Array[i] = i;
            }
            sw.Start();
            for (int i = 0; i < 1000; i++)
            {
                Console.WriteLine(Array[i]);
            }
            sw.Stop();
            Console.WriteLine("Array Takes :- " + sw.ElapsedTicks);
            Console.ReadLine();
        }
    }
}

Output:-

Check with ArrayList:-

Now, we will measure time taken in time of ArrayList. Here is sample implementation.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Diagnostics;
using System.Collections;
namespace Client
{
    class Program
    {
        static void Main(string[] args)
        {
            ArrayList li = new ArrayList(1000);
            Stopwatch sw = new Stopwatch();
            
            //Process with ArrayList, Initialization
            
            for (int i = 0; i < 1000; i++)
            {
                li.Add(i);
            }
            sw.Start();
 
            for (int i = 0; i < 1000; i++)
            {
                Console.WriteLine(li[i]);
            }
            sw.Stop();
            Console.WriteLine("ArrayList Takes :- " + sw.ElapsedTicks);
 
            Console.ReadLine();
        }
    }
}

Output:

Conclusion:-

We are seeing that in time of fetch operation Array and ArrayList is performing almost same.  So, In practical we have seen that in time of initialization Array performs well compare to ArrayList and in time of reading data both are very similar.