如何在 swift 中使用 NSNumber 和 Int 循环使用 for

Question

我是 swift 的新手，我无法获取数组的值我的数组是这样的

(
    "http://ivs.upetch.com/tpaf/storage/uploads/banner/15762295031269.jpg",
    "http://ivs.upetch.com/tpaf/storage/uploads/banner/15762294973128.jpg",
    "http://ivs.upetch.com/tpaf/storage/uploads/banner/15762294928909.jpg"
)

我的代码是这样的

    self.bannerarr = bannerdata as! NSArray
    print(self.bannerarr)

    for bannerurl in self.bannerarr{
    let stringbanner = self.bannerarr .object(at: bannerurl as! Int)
    print(stringbanner)
}

但是当我试图从数组中获取值时它显示错误为

Could not cast value of type '__NSCFString' (0x1084207a0) to 'NSNumber' (0x10493ed40).

谁能告诉我我做错了什么

Answer 1

如果您想要每个元素的索引及其值，您可以使用 enumerated() 方法遍历数组。

It returns a sequence of pairs (index, element), where index represents a consecutive integer starting at zero and element represents an element of the sequence.

  let bannerarr = ["http://ivs.upetch.com/tpaf/storage/uploads/banner/15762295031269.jpg",
    "http://ivs.upetch.com/tpaf/storage/uploads/banner/15762294973128.jpg",
    "http://ivs.upetch.com/tpaf/storage/uploads/banner/15762294928909.jpg"]

    // use your iteration as like
    for (index, element) in bannerarr.enumerated() {
      print("get Index \(index): getString \(element)")

    }

Answer 2

//初始化数据数组并return它 var 数据 = 字符串

    let formatter = NSNumberFormatter()
    formatter.numberStyle = .SpellOutStyle

    for var i = 0; i < 3; i++ {
        let number = NSNumber.init(integer: i)
        data.append(formatter.stringFromNumber(number)!)
    }

Answer 3

虽然问题已经解决了，但是我想在你的代码中告诉你循环中的'bannerurl'是元素。也许你应该知道。

Answer 4

Swift4 你也可以使用：-

for i in 0..<self.bannerarr.count{
    print("\(i) \(self.bannerarr[i])")
}

如何在 swift 中使用 NSNumber 和 Int 循环使用 for

how to use for in loop using NSNumber and Int in swift

for-in-loop

ios

swift