Minhal Khan Minhal Khan - 3 months ago 7
Swift Question

Convert a string encoded array into an object

So im getting this array in the form of a string from the server with all the coordinates of objects, shown below:

"[[[-0.340254,51.605946],[-0.340278,51.605685],[-0.339718,51.604400],
[-0.339280,51.603746],[-0.338915,51.603454],[-0.338657,51.603018],
[-0.338427,51.601810],[-0.338518,51.600885],[-0.337471,51.599908],
[-0.337378,51.599682],[-0.337456,51.599116],[-0.336860,51.597669],
[-0.335843,51.597043],[-0.335635,51.596816],[-0.335112,51.595720],
[-0.335232,51.594400],[-0.335057,51.593273],[-0.334827,51.592847],
[-0.333187,51.591889],[-0.333236,51.590945],[-0.332894,51.590446],
[-0.332727,51.589868],[-0.332791,51.589320],[-0.332638,51.589156],
[-0.332028,51.587295],[-0.332326,51.585438],[-0.332243,51.585365],
[-0.332292,51.585186],[-0.331651,51.582991],[-0.333713,51.581096],
[-0.334020,51.580570],[-0.334055,51.580013],[-0.337963,51.580123],
[-0.340047,51.579954],[-0.341778,51.579979],[-0.341883,51.579881]]]"


how would i convert this into an array?
Thank you in advance!

so i would want it the form [[Double]]

let objects = [[[-0.340254,51.605946],[-0.340278,51.605685],[-0.339718,51.604400],
[-0.339280,51.603746],[-0.338915,51.603454],[-0.338657,51.603018],
[-0.338427,51.601810],[-0.338518,51.600885],[-0.337471,51.599908],
[-0.337378,51.599682],[-0.337456,51.599116],[-0.336860,51.597669],
[-0.335843,51.597043],[-0.335635,51.596816],[-0.335112,51.595720],
[-0.335232,51.594400],[-0.335057,51.593273],[-0.334827,51.592847],
[-0.333187,51.591889],[-0.333236,51.590945],[-0.332894,51.590446],
[-0.332727,51.589868],[-0.332791,51.589320],[-0.332638,51.589156],
[-0.332028,51.587295],[-0.332326,51.585438],[-0.332243,51.585365],
[-0.332292,51.585186],[-0.331651,51.582991],[-0.333713,51.581096],
[-0.334020,51.580570],[-0.334055,51.580013],[-0.337963,51.580123],
[-0.340047,51.579954],[-0.341778,51.579979],[-0.341883,51.579881]]]


so if i was to do
objects[0][0]
it should return
[-0.340254,51.605946]


func convert(s: String) -> [[[Double]]]{

do{

let array = try NSJSONSerialization.JSONObjectWithData(s.dataUsingEncoding(NSUTF8StringEncoding)!, options: []) as? [[[Double]]]
return array!

}catch{

}
return [[[]]]


}

Answer

You simply have a JSON response of a 3D array. I loaded your string into the Swift REPL, and was able to parse it like so:

import Foundation

let s = /* your string */
let array = NSJSONSerialization.JSONObjectWithData(s.dataUsingEncoding(NSUTF8StringEncoding)!, options: []) as? [[[Double]]] 

Output

$R3: [[[Double]]]? = 1 value {
  [0] = 36 values {
...

Code Sample

func convert(s: String) -> [[[Double]]] {

    if let data = s.dataUsingEncoding(NSUTF8StringEncoding),
        let object = try? NSJSONSerialization.JSONObjectWithData(data, options: []),
        let array = object as? [[[Double]]]
    {
        return array
    }

    return [[[]]]
}
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