Swift - map dictionary based on keys

Question

Consider the dictionary :

var dict : [String : String]! = ["12" : "This", "5" : "is", "52" : "a", "42" : "Test"]

var keys = Array(dict.keys)

var values : [String]! = [String]()
for (_, key) in keys.enumerated() {
    values.append(dict[key]!)
}

Will Array(dict.values) yield the same result as above?

Is there an easier way to map the dictionary based on keys and not enumerate them?

Asking because I'd like to use the same keys to map different dictionaries for their values.

PS: It doesn't have to be sorted.

EDITED

Consider the json below :

{
  "data": {
    "forecast_numbers": {
      "15": 6397822,
      "20": 985448,
      "76": 2499160,
      "130": 4480161
    },
    "actual_numbers": {
      "15": 6344454,
      "20": 1645125,
      "76": 1644789,
      "130": 2451170
    },
    "accuracy": {
      "15": -0.83415887469204,
      "20": 66.941837621062,
      "76": -34.18632660574,
      "130": -45.288350128489
    },
    "xaxis": {
      "15": "ABC",
      "20": "BCD",
      "76": "BNM",
      "130": "NNN"
    }
  }
}

I want to plot forecast_numbers & actual_numbers values against xaxis values. Would like to know if there is an alternate way other than using enumerated() for getting the values?

I have no idea what you are trying to do, but you would get exactly the same result with `let values = Array(dict.values)`. — Martin R, Sep 26 '16 at 13:29
Perhaps `let values = keys.map { dict[$0] ?? ""}` is what you are looking for? It would allow you to get the values of another dictionary for the same keys. — Martin R, Sep 26 '16 at 13:35
@Akaino: Thank you for the suggestion, but I prefer to wait until the question has been clarified. — Martin R, Sep 26 '16 at 13:38
@MartinR Aye, you're probably right. There should be more users thinking that way. Including me, obviously. — Akaino, Sep 26 '16 at 14:06
If you only need keys... ```let the_keys: [String] = dict.keys.flatMap({ $0 })``` — Adolfo, Sep 26 '16 at 14:22

score 2 · Accepted Answer · answered Sep 26 '16 at 16:21

Your purpose is not clear enough with seeing your updated example, but if you just want to gather the values for the same key each, you can write something like this:

let data = json["data"] as! [String: [String: Any]]
let result = data["xaxis"]!.map {($0.key, $0.value, data["forecast_numbers"]![$0.key]!, data["actual_numbers"]![$0.key]!)}
print(result) //->[("130", NNN, 4480161, 2451170), ("20", BCD, 985448, 1645125), ("76", BNM, 2499160, 1644789), ("15", ABC, 6397822, 6344454)]

Assuming you have that JSON data in json as [String: AnyObject].

(Also assuming your json never contains some broken data. Seemingly using too much !.)

Thank you. was looking for something similar to this :) – Sreejith Sep 26 '16 at 17:46 — Sreejith, Sep 26 '16 at 17:46

Swift - map dictionary based on keys

1 Answers1