How to copy an ArrayList in Kotlin

How to copy an ArrayList in Kotlin.

Here's a detailed step-by-step tutorial on how to copy an ArrayList in Kotlin:

Step 1: Create an ArrayList

To begin, let's create an ArrayList that we want to copy. Here's an example of creating an ArrayList of integers:

val originalList = arrayListOf(1, 2, 3, 4, 5)

Step 2: Using the ArrayList constructor

One way to copy an ArrayList is by using the constructor of the ArrayList class. Here's how you can do it:

val copiedList = ArrayList(originalList)

In this example, we pass the originalList as an argument to the ArrayList constructor, creating a new ArrayList copiedList with the same elements.

Step 3: Using the toList() function

Another way to copy an ArrayList is by using the toList() function in Kotlin. Here's how you can do it:

val copiedList = originalList.toList() as ArrayList<Int>

In this example, we call the toList() function on the originalList, which creates an immutable List. Then, we cast it to an ArrayList<Int> to create a new ArrayList copiedList with the same elements.

Step 4: Using the addAll() function

If you want to copy an ArrayList by creating a new instance and adding all elements from the original list, you can use the addAll() function. Here's an example:

val copiedList = ArrayList<Int>()
copiedList.addAll(originalList)

In this example, we create a new ArrayList copiedList and then use the addAll() function to add all elements from the originalList to the new ArrayList.

Step 5: Using the clone() function

If you're working with mutable ArrayLists and want to create a copy, you can use the clone() function. Here's how you can do it:

val copiedList = originalList.clone() as ArrayList<Int>

In this example, we call the clone() function on the originalList and then cast it to an ArrayList<Int> to create a new ArrayList copiedList with the same elements.

Step 6: Using the toMutableList() function

If you want to create a mutable copy of an ArrayList, you can use the toMutableList() function. Here's how you can do it:

val copiedList = originalList.toMutableList()

In this example, we call the toMutableList() function on the originalList, which creates a mutable List. This mutable list can be further modified, creating a new ArrayList copiedList.

That's it! You now have multiple options to copy an ArrayList in Kotlin. Choose the method that suits your needs best.