Swift 3 : Convert Dictionary of String type to Int

Question

I' have dictionary

var dict: [String: [String]] = ["key1": ["1", "111"], "key2": ["22", "222"]]

How i can convert it to [String: [Int]] using map function

["key1": [1, 111], "key2": [22, 222]]

NOT by using for OR forEach loop

Update your example. `var dict = [String: [String]]` is invalid syntax. What do you actually have? — Mike Taverne, Mar 03 '18 at 08:08

Papershine · Accepted Answer · 2018-03-03T08:36:32.120

5

Swift 4

You can use mapValues (introduced in Swift 4) with an array map as follows

let newDict = dict.mapValues { value in 
    value.map { Int($0)!}
}

Note that your program will crash if the values inside your array can not be converted to Ints.

Swift 3

In Swift 3, however, there is no mapValues. Fortunately, with this extension (source: https://stackoverflow.com/a/24219069):

extension Dictionary {
    init(_ pairs: [Element]) {
        self.init()
        for (k, v) in pairs {
            self[k] = v
        }
    }
}

you can write

let newDict = Dictionary(dict.map { (key, value) in 
    (key, value.map{Int($0)!}) 
})

which will also achieve the desired result.

edited Mar 03 '18 at 08:36

answered Mar 03 '18 at 07:51

Papershine

I think that will only work for `var dict = [String: String]`, will it work on `var dict = [String: [String]]` as the question is suggesting. – Asis Mar 03 '18 at 08:02
@Asis `mapValues` is for the dictionary and `map` is for the array. – Papershine Mar 03 '18 at 08:07
@MikeTaverne the `mapValues(_:)` documentation states "Returns a new dictionary containing the keys of this dictionary with the values transformed by the given closure". How would it return `[Int]`? – Papershine Mar 03 '18 at 08:19
@paper1111 I stand corrected. Your solution works. Note the OP corrected his original question because it was invalid. – Mike Taverne Mar 03 '18 at 08:22
is any one give me solution in swift 3?? it will be great help – Abhishek Thapliyal Mar 03 '18 at 08:24
Seriously? You should be able to figure it out from this answer. – Mike Taverne Mar 03 '18 at 08:25
@AbhishekThapliyal I have added a Swift 3 solution – Papershine Mar 03 '18 at 08:33
@paper1111 : Now that's bit relief Thanks – Abhishek Thapliyal Mar 03 '18 at 08:35

1 Answers1