arrays - 一项一项地返回数组中的项目，直到返回所有项目，然后重新开始

Question

我想要做的是每次调用函数时都能够从数组中逐个返回项目，直到返回数组中的所有项目，然后从第一个项目重新开始。

下面的代码完全满足了我的需要，但我觉得有一种更简单的方法可以做到这一点，只是感觉我的做法很奇怪。

下面的代码有什么改进吗？

var fruits = ["Apple","Banana","blue","Orange"] 

func fruit() -> String { 
    let removedFruit = fruits.removeAtIndex(0)
    fruits.insert(removedFruit, atIndex:fruits.count)

    return removedFruit
} 

// the out put here is exactly what I need
// return Apple the first time the fruit function is called
// then return Banana the second time the function is called and so on...
print(fruit()) // Apple
print(fruit()) // Banana
print(fruit()) // Watermelon
print(fruit()) // Orange

// once all of the items in the array have been returned
// start again with the first item
print(fruit()) // Apple
print(fruit()) // Banana
print(fruit()) // Watermelon
print(fruit()) // Orange

Answer 1

不要改变数组，这很昂贵。

class FruitGenerator {
   let fruits = ["Apple", "Banana", "Poop"]
   var nextItemIndex = 0 // holds the index of item to be returned upon the next call to fruit()
   func fruit() -> String {
      let result = fruits[nextItemIndex]
      nextItemIndex = (nextItemIndex + 1) % fruits.count
      return result
   }
}