ArrayList in C# -

ArrayList in C# is a dynamically sized collection class provided by .NET framework, it allows to store and manage a list of objects of any data type.

Introduction to ArrayList in C#:

ArrayList is part of the System.Collections namespace, it is a non-generic collection that allows you to store a collection of objects that can grow or shrink dynamically in size.

Key features of ArrayList in C#:

- ArrayLists can dynamically adjust their size as you add or remove elements from the collection.
- It can hold objects of different data types within the same collection, offering flexibility for handling different types of data.
- It uses zero-based indexing while accessing the elements, just like Arrays.
- Items in the ArrayList are typically objects, so it may require boxing and unboxing while accessing elements in it.
- ArrayLists are useful when you need to handle different data types in the same collection.

Creating and Manipulating ArrayLists in C#:

To create an ArrayList, you need to include the System.Collections namespace and then instantiate an instance of the ArrayList class.

using System;
using System.Collections;

class Program
{
    static void Main()
    {
        // Create an ArrayList object
        ArrayList tempList = new ArrayList();
    }
}

using System;

using System.Collections;

class Program

{

static void Main()

{

// Create an ArrayList object

ArrayList tempList = new ArrayList();

}

Adding and Removing Elements:

You can use the Add method to add elements to an ArrayList and use the Remove or RemoveAt method to remove elements.

using System.Collections;

namespace ArrayListCollectionSample
{
    class Program
    {
        static void Main(string[] args)
        {
            //Creation of Arralist object
            ArrayList tempList = new ArrayList();

            //Adding elements to tempList
            tempList.Add(1500); //Adding an integer to the templist
            tempList.Add("Mango"); //Adding a string to the templist
            tempList.Add(true);//Adding a boolean to the templist

            // Removing elements
            tempList.Remove("Mango"); // Removes the first occurrence of "Mango"
            tempList.RemoveAt(1);     // Removes the element at index 1
        }
    }
}

using System.Collections;

namespace ArrayListCollectionSample

{

class Program

{

static void Main(string[] args)

{

//Creation of Arralist object

ArrayList tempList = new ArrayList();

//Adding elements to tempList

tempList.Add(1500); //Adding an integer to the templist

tempList.Add("Mango"); //Adding a string to the templist

tempList.Add(true);//Adding a boolean to the templist

// Removing elements

tempList.Remove("Mango"); // Removes the first occurrence of "Mango"

tempList.RemoveAt(1); // Removes the element at index 1

}

In the above example,

- We have created a ArrayList object as tempList and added a string (“Mango“) , integer (1500) and boolean (true) to it.
- tempList.Remove("Mango") removes “Mango” and tempList.RemoveAt(1) removes boolean value true from the tempList.

Accessing ArrayList Elements:

ArrayList uses zero-based indexing while accessing the elements, just like arrays.

using System;
using System.Collections;

class Program
{
    static void Main()
    {
        ArrayList myList = new ArrayList();

        myList.Add("Apple");
        myList.Add("Banana");
        myList.Add("Orange");

        // Accessing elements
        string firstFruit = (string)myList[0];
        string secondFruit = (string)myList[1];
    }
}

using System;

using System.Collections;

class Program

{

static void Main()

{

ArrayList myList = new ArrayList();

myList.Add("Apple");

myList.Add("Banana");

myList.Add("Orange");

// Accessing elements

string firstFruit = (string)myList[0];

string secondFruit = (string)myList[1];

}

In this example,

- We create an ArrayList called myList and add elements to it, using the zero-based index we access items from it.

Example 1: Create and use an ArrayList in C#

using System;
using System.Collections;

class Program
{
    static void Main()
    {
        // Create an ArrayList
        ArrayList myList = new ArrayList();

        // Add elements to the ArrayList
        myList.Add("Apple");
        myList.Add(42);
        myList.Add(true);

        // Access elements
        Console.WriteLine(myList[0]); // Output: Apple
        Console.WriteLine(myList[1]); // Output: 42
        Console.WriteLine(myList[2]); // Output: True

        // Remove an element
        myList.Remove("Apple");

        // Count of elements
        Console.WriteLine("Number of elements: " + myList.Count); // Output: Number of elements: 2
    }
}

using System;

using System.Collections;

class Program

{

static void Main()

{

// Create an ArrayList

ArrayList myList = new ArrayList();

// Add elements to the ArrayList

myList.Add("Apple");

myList.Add(42);

myList.Add(true);

// Access elements

Console.WriteLine(myList[0]); // Output: Apple

Console.WriteLine(myList[1]); // Output: 42

Console.WriteLine(myList[2]); // Output: True

// Remove an element

myList.Remove("Apple");

// Count of elements

Console.WriteLine("Number of elements: " + myList.Count); // Output: Number of elements: 2

}

In this example,

- We create an ArrayList called myList and add elements of different data types, e.g Apple (String type), 42 (Interger type) and true (boolean type) to myList.
- We have used zero-based indexing and able to access the values and print in the console.
- We have also removed an item using the Remove method and display the count of elements in the ArrayList by using Count method.

When we run above example, it generates following output.

ArrayList Methods and Properties in C#:

ArrayLists offer various methods and properties for manipulation and information retrieval.

Count : We use the Count property to determine the number of elements.
Sort : The Sort method arranges the elements in ascending order.
Contains : The Contains method checks if the ArrayList contains a specific element.
Reverse : The Reverse method reverses the order of elements.

Example 2 : Showcase various ArrayList methods and properties in C#

using System;
using System.Collections;

namespace ArrayListCollectionSample
{
    class Program
    {
        static void Main(string[] args)
        {
            ArrayList tempList = new ArrayList();

            // Adding elements
            tempList.Add("Grapes");
            tempList.Add("Orange");
            tempList.Add("Mango");
            tempList.Add("Banana");
            tempList.Add("Watermelon");

            // Count property
            int itemCount = tempList.Count; // Returns the number of elements in the ArrayList
            Console.WriteLine($"Number of elements in the tempList : {itemCount}");

            // Sorting the elements
            tempList.Sort(); // Sorts the elements in ascending order

            // Displaying the modified ArrayList
            Console.WriteLine("Modified ArrayList after tempList.Sort() execution:");
            Console.WriteLine("**********************************************************");
            foreach (object item in tempList)
            {
                Console.WriteLine(item);
            }
            Console.WriteLine("**********************************************************");
            // Checking if an element exists
            bool hasApple = tempList.Contains("Orange");
            Console.WriteLine($"tempList has Orange ? : {hasApple}");

            // Accessing elements
            string secondElement = (string)tempList[1];
            Console.WriteLine($"Second element in tempList: {secondElement}");

            // Removing an element
            tempList.Remove("Banana"); // Removes "Banana"
            Console.WriteLine("Removes Banana from tempList using tempList.Remove().");

            // Reversing the elements
            tempList.Reverse(); // Reverses the order of elements

            // Displaying the modified ArrayList
            Console.WriteLine("Modified ArrayList after tempList.Reverse() execution:");
            Console.WriteLine("**********************************************************");
            foreach (object item in tempList)
            {
                Console.WriteLine(item);
            }
            Console.WriteLine("**********************************************************");
        }
    }
}

using System;

using System.Collections;

namespace ArrayListCollectionSample

{

class Program

{

static void Main(string[] args)

{

ArrayList tempList = new ArrayList();

// Adding elements

tempList.Add("Grapes");

tempList.Add("Orange");

tempList.Add("Mango");

tempList.Add("Banana");

tempList.Add("Watermelon");

// Count property

int itemCount = tempList.Count; // Returns the number of elements in the ArrayList

Console.WriteLine($"Number of elements in the tempList : {itemCount}");

// Sorting the elements

tempList.Sort(); // Sorts the elements in ascending order

// Displaying the modified ArrayList

Console.WriteLine("Modified ArrayList after tempList.Sort() execution:");

Console.WriteLine("**********************************************************");

foreach (object item in tempList)

{

Console.WriteLine(item);

}

Console.WriteLine("**********************************************************");

// Checking if an element exists

bool hasApple = tempList.Contains("Orange");

Console.WriteLine($"tempList has Orange ? : {hasApple}");

// Accessing elements

string secondElement = (string)tempList[1];

Console.WriteLine($"Second element in tempList: {secondElement}");

// Removing an element

tempList.Remove("Banana"); // Removes "Banana"

Console.WriteLine("Removes Banana from tempList using tempList.Remove().");

// Reversing the elements

tempList.Reverse(); // Reverses the order of elements

// Displaying the modified ArrayList

Console.WriteLine("Modified ArrayList after tempList.Reverse() execution:");

Console.WriteLine("**********************************************************");

foreach (object item in tempList)

{

Console.WriteLine(item);

}

Console.WriteLine("**********************************************************");

}

In this example,

- We create an ArrayList called myList and perform various operations using its methods and properties.

When we run the above program, it produces below output.

Difference between Array and Arraylist in C#:

Arrays	ArrayLists
We have to specify the Array size during declaration.	ArrayList is dynamically resizable, and no size specification required.
Array holds elements of a specific data type.	ArrayList store elements of various data types.
We can’t change array size after declaration.	It grows dynamically or shrinks as elements are added or removed.
Generally better performance due to fixed size and direct memory access.	Potentially slower performance due to dynamic resizing and value type boxing/unboxing.
Array is typically Type-safe, elements must have the same data type.	ArrayList is not Type-safe, can hold different data types.
Memory allocated in a contiguous block, may lead to memory wastage.	Internally manages memory allocation and resizing.
No type conversion required for element access.	Accessing an element may requires type conversion (boxing/unboxing).
Suitable for fixed-size collections with the same data type.	Useful for dynamic collections with varying data types.

ArrayList or List<T> in C#? Which one is better?

Let’s compare between non generic ArrayList and generic collection List<T> and understand which one is better.

- List<T> is a strong typed, it ensures that all elements within the collection are of the specified type.
- ArrayList stores elements as objects, which requires boxing (converting value types to object types) and unboxing (converting back to value types). This boxing and unboxing can lead to performance overhead and memory allocation. List<T> is strongly typed and hence avoids boxing and unboxing, which results in better performance.
- Compile time type checking is feasible in List<T>, making it easier to catch type-related errors during development. This leads to more reliable and maintainable code.
- List<T> is strongly typed which is more memory efficient, whereas ArrayList requires additional memory for boxing value types and storing objects.

Conclusion:

In conclusion, if you’re working with collections of the same data type, List<T> is the recommended choice due to its advantages, ArrayList might still be used in legacy codebases or in scenarios where you are handling different data type collection.

Thanks for visiting, please go through my other articles on similar topics List in C# and Dictionary in C# – Collection Class

ArrayList in C#

Introduction to ArrayList in C#:

Creating and Manipulating ArrayLists in C#:

Adding and Removing Elements:

Accessing ArrayList Elements:

Example 1: Create and use an ArrayList in C#

ArrayList Methods and Properties in C#:

Example 2 : Showcase various ArrayList methods and properties in C#

Difference between Array and Arraylist in C#:

Arrays

ArrayLists

ArrayList or List<T> in C#? Which one is better?

Conclusion:

Like this:

Related

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Introduction to ArrayList in C#:

Creating and Manipulating ArrayLists in C#:

Adding and Removing Elements:

Accessing ArrayList Elements:

Example 1: Create and use an ArrayList in C#

ArrayList Methods and Properties in C#:

Example 2 : Showcase various ArrayList methods and properties in C#

Difference between Array and Arraylist in C#:

Arrays

ArrayLists

ArrayList or List<T> in C#? Which one is better?

Conclusion:

Share this:

Like this:

Related

Leave a ReplyCancel reply