Extract a String to array of CGPoints in Swift - arrays

Question

I have a string containing a list of thousands of geo coordinates
"[8.2627925,46.3460497],[8.2612673,46.3457009],[8.2602494,46.3453934],..."
and would like to extract all of them in an array of CGPoints.
The code I am using today is the following:
let coords=[CGPoint]()
while substring.contains("[")
{
index = substring.index(of: "[")!
substring = substring[index...]
index = substring.index(of: "]")!
let coordinate = substring[..<index]
var indexComma = coordinate.index(of: ",")!
let coordX = String(coordinate[..<indexComma])
indexComma = coordinate.index(indexComma, offsetBy: +1)
let coordY = String(coordinate[indexComma...])
coords.append(CGPoint(x: CGFloat(Double(coordX)!), y: CGFloat(Double(coordY)!)))
substring = substring[index...]
}
However I am sure it can be optimised, possibly using regex. What would be the most efficient way ?

Answer 1

One of the better efficient way is using to json serialization. Json can not serialize your string because its not in to correct format so you can insert "[" and "]" for serialize it like below
var coordinates = "[1.3123,3.2131],[2.3123,4.213]"
coordinates.insert("[", at: coordinates.startIndex)
coordinates.insert("]", at: coordinates.endIndex)
Now , our data is ready for serialization.Then the easiest part is appending poinst to CGPoint array
var points : [CGPoint] = []
if let data = coordinates.data(using: .utf8),
let jsonArray = try? JSONSerialization.jsonObject(with: data) as? [[Double]] {
points.append(contentsOf: jsonArray.map{CGPoint(x: $0[0], y: $0[1]) })
print(points)
}
You can easily reach ur datas
print(points[0].x) // 1.3123
print(points[1].y) // 4.213