无法快速从Array数据转换为CLLocationCoordinate2D以在mapview中绘制折线

Question

I have array ( coordinatesArray ) of data which has double values like following.

(
    "-61.4149691",
    "42.9572076"
)
(
    "-61.4126004",
    "42.9572026"
)
(
    "-61.476674304",
    "42.9572032"
)

This is mapData

 (
        "-61.4149691",
        "42.9572076"
 )

So, I took a loop for converting each index data as latitude and longitude by converting as double.

 if let coordinatesArray = geoMetrys.value(forKey: "coordinates") as? NSArray {
    for mapData in coordinatesArray {
     print(mapData)

  let latitude = (mapData[0] as NSString).doubleValue
  let longitude = (mapData[1] as NSString).doubleValue

  var coordinatesToAppend: CLLocationCoordinate2D? = [latitude, longitude]

  var polyline = MKPolyline(coordinates: &coordinatesToAppend!, count: coordinatesArray.count)
 mapView.add(polyline)

But, its showing error while compiling time.

 `Type 'Any' has no subscript members` for following lines 

  let latitude = (mapData[0] as NSString).doubleValue
  let longitude = (mapData[1] as NSString).doubleValue

I have an array in that I have data of value as latitude and longitude. So, I am trying to draw a polyline in mapview with these values.

Can anyone suggest me where I am failing to achieve this?

Answer 1

In your code, the line

if let coordinatesArray = geoMetrys.value(forKey: "coordinates") as? NSArray

returns an array of type Any (ie [Any] ). After that, when you use the for loop

for mapData in coordinatesArray

you are essentially looping over an array of Any where, in every iteration, an item (of type Any ) is assigned to mapData . Now if this mapData is an array itself, you have to explicitly specify it as

if let dataArray = mapData as? NSArray {
    let latitude = (dataArray[0] as NSString).doubleValue
    let longitude = (dataArray[1] as NSString).doubleValue
}