Question

嗨，我对swift相对较新。我想要构建一个数组，其中包含来自下面显示的字符串的元组数组。每个数组中元组的数量并不总是恒定的。最终的数据结构是： [[（Double，Double）]]

要解析的字符串： “（（2363448.9 5860581.3,2363438.0 5860577.9），（2363357.5 5860494.7,2363303.2 5860502.0,2363282.5 5860502.5），（2363357.5 5860494.7），（......... etc））”

我想知道是否有人对最佳/最有效的方式有任何想法。我正在考虑迭代原始字符串并按遇到的字符设置标记。然后为东边和北边建造弦乐。但我不确定这是不是最好的方式，看起来过于复杂。效率是一个因素，因为字符串有时可能非常大。

- UPDATE 这是我到目前为止的代码，似乎有效。对改进的想法或更好的方法表示赞赏，因为代码有点混乱。感谢迄今为止帮助过的所有人。

typealias Coordinate = (easting: Double, northing: Double)
typealias Coordinates = [[Coordinate]]

var array = Array<Array<Coordinate>>() //Array of array of tuples(Double)
var tupleArray = [Coordinate]() //Array of tuples(Double)
var tuple: (Double, Double)! = (0, 0)
var easting: Bool = false
var northing: Bool = false
var eastingString: String = ""
var northingString: String = ""
var openBracket = 0
let tempString = getSubstringFromIndex(wktGeometry , character: "G") //string to parse
for char in tempString.characters {
   if char == "(" {
       openBracket++
       if openBracket == 2 {
           easting = true
       }
   } else if char == ")" {
       openBracket--
       if openBracket == 1 {
           tuple.1 = Double(northingString)!
           tupleArray.append(tuple)
           array.append(tupleArray)
           tupleArray = [Coordinate]()
           eastingString = ""
           northingString = ""
       }
   } else if char == "," {
       if openBracket == 2 {
           tuple.1 = Double(northingString)!
           tupleArray.append(tuple)
           eastingString = ""
           northingString = ""
        }
   } else if char == " " {
       if easting == true {
           tuple.0 = Double(eastingString)!
           easting = false
           northing = true
       } else {
           northing = false
           easting = true
       }
    } else {
        if easting {
            eastingString += String(char)
        } else if northing {
            northingString += String(char)
        }
    } //end if
} //end for
print(array)

Answer 1

您的代码问题在于您尝试一次完成所有操作。如果将任务拆分为小的子任务，它将变得更加简单：

// will parse "2363448.9 5860581.3"
func parseCoordinate(coordinateString: String) -> (Double, Double) {
   // possible implementation:
   // 1. split string by space,
   // 2. assert there are two components
   // 3. parse them to Doubles and return them
}

// will parse "(2363448.9 5860581.3, 2363438.0 5860577.9)"
func parseCoordinates(coordinatesString: String) -> [(Double, Double)] {
   // possible implementation:
   // 1. remove last character "(" and end character ")"
   // 2. split the string by "," + remove spaces around results
   // 3. call parseCoordinate for every result (e.g. using "map" method)
}

// will parse your whole string
func parse(string: String) -> [[(Double, Double)]] {
   // possible implementation
   // 1. Use a smart regular expression to split by "," not inside "(" and ")" or just by string "), ("
   // 2. call parseCoordinates for every result (e.g. using "map" method)
}

最重要的是：

字符串拆分（请参阅https://stackoverflow.com/a/25678505/669586）
Array.map方法

Answer 2

基本上[[2363448.9 5860581.3, 2363438.0 5860577.9], [2363357.5 5860494.7, 2363303.2 5860502.0], [2363282.5 5860502.5, 2363357.5 5860494.7]]将使用上面提到的trojanfoe的JSON代码。除此之外，您可以使用变量来存储它们，并在使用追加时添加它们。它肯定看起来更干净，除非你拥有的是一个常数。

协调字符串解析

2 个答案: