Convert string array description to array

Question

I have the following code:

var data = [12,33,22,44];
var a =  data.description;  // results is "[12,33,22,44]"
var new = Array(a); // result is ['[','1'.  not [12,33,22,44]

Aside splitting 'a' and iterating the result, There is a fastest way to convert a string to an array ?

Thanks

I think he wants a solution for a scenario where only the description of the array is available. — Luca Angeletti
– Luca Angeletti, Commented Aug 14, 2015 at 13:17

Kirsteins · Accepted Answer · 2015-08-14 13:07:50Z

4

You can do that by splitting array and filtering all elements that cannot be converted to Int.

 "[12,33,22,44]".componentsSeparatedByCharactersInSet(NSCharacterSet(charactersInString: "[,]")).filter{ $0.toInt() != nil }.map{ $0.toInt()! } // [12, 33, 22, 44]

answered Aug 14, 2015 at 13:07

Kirsteins

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Comments

Rob · Accepted Answer · 2015-08-14 14:20:30Z

You can

trim the [ and ] characters with stringByTrimmingCharactersInSet;
split it into an array of components separated by commas; and
trim whitespace around each item.

For example:

let array = [12,33,22,44];
let string = array.description;  // result is "[12, 33, 22, 44]", not "[12,33,22,44]"

let results = string
    .stringByTrimmingCharactersInSet(NSCharacterSet(charactersInString: "[]"))
    .componentsSeparatedByString(",")
    .map { return $0.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceAndNewlineCharacterSet()) }

Or if you want an array of integers instead of an array of strings:

let results = string
    .stringByTrimmingCharactersInSet(NSCharacterSet(charactersInString: "[]"))
    .componentsSeparatedByString(",")
    .map { return $0.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceAndNewlineCharacterSet()).toInt()! }  // remove `!` if you're not assured that only integers will be present

Eric Aya · Accepted Answer · 2016-04-21 09:05:34Z

2

A safe way of doing this is to encode the String as data then decode the data as JSON and finally downcast the result as an array of Ints:

let base = [12,33,22,44]
let source = base.description
if let data = source.dataUsingEncoding(NSUTF8StringEncoding) {
    if let arrayOfInts = try NSJSONSerialization.JSONObjectWithData(data, options: []) as? [Int] {
        print(arrayOfInts) // [12, 33, 22, 44]
        print(arrayOfInts[1]) // 33
    }
}

answered Apr 21, 2016 at 9:05

Eric Aya

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Comments

Chanraksmey · Accepted Answer · 2017-06-09 09:44:46Z

1

Swift 3 code:

let results = "[12,33,22,44]"
              .trimmingCharacters(in: CharacterSet(charactersIn: "[]"))
              .components(separatedBy:",")

print("Result array: \(results)")

answered Jun 9, 2017 at 9:44

Chanraksmey

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Comments

elyrico · Accepted Answer · 2016-04-21 09:00:48Z

0

Rob's answer for Swift 2.2

let results = value
            .stringByTrimmingCharactersInSet(NSCharacterSet(charactersInString: "[]"))
            .componentsSeparatedByString(",")
            .map { return Int($0.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceAndNewlineCharacterSet()))!}  // remove `!` if you're not assured that only integers will be present

answered Apr 21, 2016 at 9:00

elyrico

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