ODG - Kotlin: Avoiding ConcurrentModificationException

AvoidConcurrentModificationException.kt

val integers = arrayListOf(1, 2, 3)

// Filter using streams.
val newIntegers = integers.filter { it != 2 }

// Use removeIf()
integers.removeIf { it == 2 }

// Use an iterator directly.
val iterator = integers.iterator()
while (iterator.hasNext()) {
  val integer = iterator.next()
  if (integer == 2) {
    iterator.remove()
  }
}

// Remove after iteration.
val toRemove = arrayListOf<Int>()
  for (i in integers) {
    if (i == 2) {
      toRemove.add(i)
    }
}
integers.removeAll(toRemove)