Converting a single string with coordinates into an array of CLLocationCoordinate2D and use the array to generate Polygons in a mapView

Question

I'm receiving this JSON:

JSON: {
  "status_code" : 200,
  "status" : "ok",
  "data" : [
    {
      "zona" : "Narvarte",
      "hora" : "",
      "id_zona" : 1423,
      "proxdia" : "Lunes 20 de Febrero, 2017",
      "coor" : "(19.452187074041884, -99.1457748413086),(19.443769985032485, -99.14852142333984),(19.443446242121073, -99.13787841796875),(19.450244707639662, -99.13822174072266)",
      "dias" : "Lunes"
    }, ...]

Which I'm storing in this struct:

struct RutaItem {
var idZona: Int
var dias: String
var proxDia: String
var hora: String
var coor: String
var zona: String
}

then I created an array of [RutaItem] where I'm storing the structs

var rutaItemArray = [RutaItem]()

Once the data has been stored the structs inside rutaItemArray look like this:

[pixan.RutaItem(idZona: 1423, dias: "Lunes", proxDia: "Lunes 20 de Febrero, 2017", hora: "", coor: "(19.452187074041884, -99.1457748413086),(19.443769985032485, -99.14852142333984),(19.443446242121073, -99.13787841796875),(19.450244707639662, -99.13822174072266)", zona: "Narvarte")...]

What I need to do now is to use the String inside each index of rutaItemArray.coor to generate an MKPolygonObject, so first I would need to convert the long String into 4 CLLocationCoordinate2D objects and put those 4 coordinate objects inside an array for each item, then use the array indexes to generate the polygon.for the different areas.

Can somebody help me with this problem?

Answer 1

You can use regular expression pattern matching. Explanations inline:

let coordString = "(19.452187074041884, -99.1457748413086), (19.443769985032485, -99.14852142333984),(19.443446242121073, -99.13787841796875),(19.450244707639662, -99.13822174072266)"

// Regular expression pattern for "( ... , ... )"
let pattern = "\\((.+?),(.+?)\\)"
let regex = try! NSRegularExpression(pattern: pattern)

// We need an NSString, compare http://stackoverflow.com/a/27880748/1187415
let nsString = coordString as NSString

// Enumerate all matches and create an array: 
let coords = regex.matches(in: coordString, range: NSRange(location: 0, length: nsString.length))
    .flatMap { match -> CLLocationCoordinate2D? in
        // This closure is called for each match.

        // Extract x and y coordinate from match, remove leading and trailing whitespace:
        let xString = nsString.substring(with: match.rangeAt(1)).trimmingCharacters(in: .whitespaces)
        let yString = nsString.substring(with: match.rangeAt(2)).trimmingCharacters(in: .whitespaces)

        // Convert to floating point numbers, skip invalid entries:
        guard let x = Double(xString), let y = Double(yString) else { return nil }

        // Return CLLocationCoordinate2D:
        return CLLocationCoordinate2D(latitude: x, longitude: y)
}