How to Convert an `IntArray` to `ArrayList<Int>` in Kotlin?

Question

What is the correct method to convert an `IntArray` to an `ArrayList<Int>` in Kotlin?

val array = intArrayOf(5, 3, 0, 2, 4, 1, 0, 5, 2, 3, 1, 4)

Answer

In Kotlin, converting an `IntArray` to an `ArrayList<Int>` can be accomplished with a couple of simple steps. It involves first converting the `IntArray` to a standard array, and then creating an `ArrayList` from that standard array.

val intArray = intArrayOf(5, 3, 0, 2, 4, 1, 0, 5, 2, 3, 1, 4)
val arrayList: ArrayList<Int> = ArrayList(intArray.toList())

Causes

  • Understanding the difference between `IntArray` and other array types in Kotlin.
  • The method `toTypedArray()` only converts `IntArray` to `Array<Int>`, not directly to `ArrayList<Int>`.
  • Not using the appropriate constructor or collection function available in Kotlin.

Solutions

  • Use the `asList()` method in combination with `ArrayList` to efficiently convert.

Common Mistakes

Mistake: Using `toTypedArray()` expecting it will return an `ArrayList<Int>` directly.

Solution: Use `toList()` followed by `ArrayList()` constructor to create the desired ArrayList.

Mistake: Not initializing the `ArrayList` correctly.

Solution: Ensure you create the `ArrayList` properly from a collection obtained from the `IntArray`.

Helpers

  • Kotlin IntArray conversion
  • Array to ArrayList Kotlin
  • convert IntArray to ArrayList<Int>
  • Kotlin collection conversion

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