How to Create 2D array in Swift?

Question

Hi there I am new to Swift, I am trying to save Longitude and Latitude and place name from map's coordinate object to an Multidimensional array i.e:

Can anyone please help me how do i create these dynamically?

var pinArray[0][Lat] = 51.130231
var pinArray[0][Lon] = -0.189201
var pinArray[0][Place] = "Home"

var pinArray[1][Lat] = 52.130231
var pinArray[1][Lon] = -1.189201
var pinArray[1][Place] = "Office"

var pinArray[2][Lat] = 42.131331
var pinArray[2][Lon] = -1.119201
var pinArray[2][Place] = "Dinner"

Might need a little more context on this. What does your input data look like? — Beau Nouvelle
– Beau Nouvelle, Commented Jan 14, 2016 at 22:59
Hi Beau I Looks as shown in question there is longitude, latitude, place name — Keyur Padalia
– Keyur Padalia, Commented Jan 14, 2016 at 23:00
Of course, but are these hard coded values, or are they coming from something in JSON format for example. Could you not just loop through that data? Is that what you want? — Beau Nouvelle
– Beau Nouvelle, Commented Jan 14, 2016 at 23:02

Eric Aya · Accepted Answer · 2016-01-14 23:12:58Z

You can make an array of dictionaries, but I suggest using structs instead.

Array of dictionaries

Create an empty array of dictionaries:

var pinArray = [[String:AnyObject]]()

Append dictionaries to the array:

pinArray.append(["lat":51.130231, "lon":-0.189201, "place":"home"])

pinArray.append(["lat":52.130231, "lon":-1.189201, "place":"office"])

But since your dictionaries hold two types of value (Double and String) it will be cumbersome to get the data back:

for pin in pinArray {
    if let place = pin["place"] as? String {
        print(place)
    }
    if let lat = pin["lat"] as? Double {
        print(lat)
    }
}

So, better use structs instead:

Array of structs

Create a struct that will hold our values:

struct Coordinates {
    var lat:Double
    var lon:Double
    var place:String
}

Create an empty array of these objects:

var placesArray = [Coordinates]()

Append instances of the struct to the array:

placesArray.append(Coordinates(lat: 51.130231, lon: -0.189201, place: "home"))

placesArray.append(Coordinates(lat: 52.130231, lon: -1.189201, place: "office"))

It's then easy to get the values:

for pin in placesArray {
    print(pin.place)
    print(pin.lat)
}

Beau Nouvelle · Accepted Answer · 2016-01-14 23:07:28Z

1

Without more information, this is what I can offer.

var pinArray = [[AnyObject]]()

for location in mapLocations {
    var innerArray = [location["latitude"], location["longitude"], location["place"]]
    pinArray.append(innerArray)
}

answered Jan 14, 2016 at 23:07

Beau Nouvelle

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1 Comment

Keyur Padalia Over a year ago

That's exactly what i was looking for Beau Thanks

dfrib · Accepted Answer · 2016-01-14 23:12:48Z

Solution using an enum for Lat/Lon/Place (as you don't show us what these are):

enum Pos {
    case Lat
    case Lon
    case Place

    static let allPositions = [Lat, Lon, Place]
}

var myMatrix = [[Pos:Any]]()
myMatrix.append([.Lat: 51.130231, .Lon: -0.189201, .Place: "Home"])
myMatrix.append([.Lat: 52.130231, .Lon: -1.189201, .Place: "Office"])
myMatrix.append([.Lat: 42.131331, .Lon: -1.119201, .Place: "Dinner"])

/* check */
for (i,vector) in myMatrix.enumerate() {
    for pos in Pos.allPositions {
        print("myMatrix[\(i)][\(pos)] = \(vector[pos] ?? "")")
    }
}
/*
myMatrix[0][Lat] = 51.130231
myMatrix[0][Lon] = -0.189201
myMatrix[0][Place] = Home
myMatrix[1][Lat] = 52.130231
myMatrix[1][Lon] = -1.189201
myMatrix[1][Place] = Office
myMatrix[2][Lat] = 42.131331
myMatrix[2][Lon] = -1.119201
myMatrix[2][Place] = Dinner    */

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How to Create 2D array in Swift?

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Array of dictionaries

Array of structs

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