Question

我有一个包含2个数组的数组A：

[[Sunday, Monday, Tuesday, Wednesday, Thursday, Friday, Saturday], [Monday, Wednesday]]

现在我想用以下代码替换数组A的元素：

[[Sun, Mon, Tue, Wed, Thu, Fri, Sat], [Mon, Wed]]

为此，我打算使用：

for days in operatingDays {
  for weekdays in days
  {
  if (operatingDays[i] as? String == "Sun") {
    operatingDays[i] = "Su"
  } else if operatingDays[i] as? String == "Mon"{
    operatingDays[i] = "Mo"
  } else if operatingDays[i] as? String == "Tue"{
    operatingDays[i] = "Tu"
  } else if operatingDays[i] as? String == "Wed"{
    operatingDays[i] = "We"
  } else if operatingDays[i] as? String == "Thu"{
    operatingDays[i] = "Th"
  } else if operatingDays[i] as? String == "Fri"{
    operatingDays[i] = "Fr"
  } else if operatingDays[i] as? String == "Sat"{
    operatingDays[i] = "Sa"
  }
}
}

但它显示错误：但是如何在Swift3中实现这一点，我们将不胜感激。

Answer 1

var input = [["Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"], ["Monday", "Wednesday"]]

var output = [[String]]()

for array in input {
    output.append(array.map {String($0.characters.prefix(3))})
}

输出将包含[["Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"], ["Mon", "Wed"]]

Answer 2

将operatingDays视为更具体的内容

for days in operatingDays as! [[String]]

Answer 3

您可以使用AnyObject类型来投射数组，例如此代码可以帮助您：

var array: [AnyObject] = [[Sunday, Monday, Tuesday, Wednesday, Thursday, Friday, Saturday], [Monday, Wednesday]]
array = [[Sun, Mon, Tue, Wed, Thu, Fri, Sat], [Mon, Wed]]

现在，如果你想做一些特别的事情，你必须施放那个数组：

if let item = array[2] as? String{
    print(item)
}

或者您只需打印阵列：

for item in array{
    print("my item is \(item)")
}

Answer 4

尝试使用此功能，正如我所说，您需要将日期设为[String]

for days in operatingDays {
        if let daysArray = days as? [String]
        {
            for weekdays in daysArray
            {
               operatingDays[i] = 
                if (operatingDays[i] as? String == "Sun") {
                    operatingDays[i] = "Su"
                } else if operatingDays[i] as? String == "Mon"{
                    operatingDays[i] = "Mo"
                } else if operatingDays[i] as? String == "Tue"{
                    operatingDays[i] = "Tu"
                } else if operatingDays[i] as? String == "Wed"{
                    operatingDays[i] = "We"
                } else if operatingDays[i] as? String == "Thu"{
                    operatingDays[i] = "Th"
                } else if operatingDays[i] as? String == "Fri"{
                    operatingDays[i] = "Fr"
                } else if operatingDays[i] as? String == "Sat"{
                    operatingDays[i] = "Sa"
                }
            }
        }
    }

希望这有帮助

如何用swift3中的其他元素替换数组的值？

4 个答案: