CODEWITHSUNDEEP
arraysswiftmultidimensional-arrayfor-in-loop
Lonely Twinky
Lonely Twinky

Reputation: 465

Address each dimension of a 3-D array in swift

I've been trying for the past few days learn how to insert data into every index in a 3-D array in swift. I am attempting to populate a 3-D array through a for-in loop. I know this example isn't correct because I'm not address each dimension in the array when I attempt to place in a value for the array, but I don't know how else to show what I mean:

var arr = [[[String]]]()
var brand = ["ford", "dodge", "toyota", "ford", "Nissan"]
var engine = ["2.0", "2.5", "3.4", "4.0", "5.0"]
var gas_mile = ["30", "25", "20", "15", "10"]

for index_1 in 1...brand.count{
    arr[index_1] = brand[index_1]

    for index_2 in 1...engine.count{
        arr[index_1][index_2] = engine[index_2] 

        for index_3 in 1...gas_mile.count{
             arr[index_1][index_2][index_3] = gas_mile[index_3]
        }
    }
}

I know you need to have an index for every dimension of the array ex:

 arr[0][0][0] = gas_mile[0]

But I don't know how you would then add something to the first dimension of the array because the swift compiler is expecting a 2-D array ([[String]]) to be added, not a single value:

arr[0] = brand[0]

So I am confused how I would address the first or second dimension of the array in adding a value to it. I have little experience with swift, that's why I am asking on how you can address each individual dimension.

Upvotes: 0

Views: 49

Answers (1)

Luca Angeletti
Luca Angeletti

Reputation: 59506

Here's a possible solution

struct Archive {
    private var dict = [String:[String:Int]]()

    func miles(byBrand brand: String, andEngine engine: String) -> Int? {
        return dict[brand]?[engine]
    }

    mutating func set(miles: Int, forBrand brand: String, andEngine engine:String) {
        var milesDict = dict[brand] ?? [String:Int]()
        milesDict[engine] = miles
        dict[brand] = milesDict
    }
}

How does it work?

As you can see data is stored in a dictionary where the key is the brand name and the value is another dictionary which has as key the engine and as value the miles.

How to use it

Step 1: create your Archive value

var archive = Archive()

Step 2: store data

archive.set(miles: 1, forBrand: "Ford", andEngine: "2.0")
archive.set(miles: 2, forBrand: "Ford", andEngine: "3.0")
archive.set(miles: 3, forBrand: "Ford", andEngine: "4.0")
archive.set(miles: 4, forBrand: "Ford", andEngine: "5.0")
archive.set(miles: 5, forBrand: "Audi", andEngine: "2.0")

Step 3: read data

archive.miles(byBrand: "Ford", andEngine: "2.0") // 1
archive.miles(byBrand: "Ford", andEngine: "3.0") // 2
archive.miles(byBrand: "Ford", andEngine: "4.0") // 3
archive.miles(byBrand: "Ford", andEngine: "5.0") // 4
archive.miles(byBrand: "Audi", andEngine: "3.0") // 5

Upvotes: 1

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