Sequences: Implementation of the drop

The drop decorator has a similar structure to the take decorator. It also maintains an internal counter and returns elements until the counter reaches zero.

    override fun iterator(): Iterator<T> = object : Iterator<T> {
        val iterator = sequence.iterator()
        var left = count

        // Shouldn't be called from constructor to avoid premature iteration
        private fun drop() {
            while (left > 0 && iterator.hasNext()) {
                iterator.next()
                left--
            }
        }

        override fun next(): T {
            drop()
            return iterator.next()
        }

        override fun hasNext(): Boolean {
            drop()
            return iterator.hasNext()
        }
    }

You can learn more from my sequences performance study “Measuring sequences”