How to convert an array of custom objects to an array of strings?

Question

I currently have an array of custom objects

[GenrePosters]

which is defined like so:

public struct GenrePosters: Decodable, Equatable{

  public let poster : String

  public init? (json: JSON) {

    guard let poster: String = "poster_path" <~~ json
      else {return nil}
    self.poster = poster
  }

  public static func ==(lhs: GenrePosters, rhs: GenrePosters) -> Bool {
    return lhs.poster == rhs.poster
  }

When printed to console it looks like this:

[MyMovieGuide.GenrePosters(poster: "/e1mjopzAS2KNsvpbpahQ1a6SkSn.jpg"), MyMovieGuide.GenrePosters(poster: "/jjBgi2r5cRt36xF6iNUEhzscEcb.jpg"), MyMovieGuide.GenrePosters(poster: "/tIKFBxBZhSXpIITiiB5Ws8VGXjt.jpg")]

I'm trying to convert the array of GenrePosters to an array of strings with only the poster values that like this:

[ "/e1mjopzAS2KNsvpbpahQ1a6SkSn.jpg" "/jjBgi2r5cRt36xF6iNUEhzscEcb.jpg" "/tIKFBxBZhSXpIITiiB5Ws8VGXjt.jpg"]

Any help will be appreciated!

Possible duplicate of Get an array of property values from an object array — Hamish
– Hamish, Commented Feb 3, 2017 at 20:07
I see you using the tmdb haha. Came here for a different reason, but just did a project using this. — Robert Bentley
– Robert Bentley, Commented May 18, 2023 at 21:17

Sergey Kalinichenko · Accepted Answer · 2017-02-03 19:51:31Z

18

You should be able to do this using map(_:) method:

let posters = posterList.map {$0.poster}

edited Feb 3, 2017 at 19:51

answered Feb 3, 2017 at 19:49

Sergey Kalinichenko

729k85 gold badges1.2k silver badges1.6k bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

rmaddy Over a year ago

What about let posters = posterList.map{ $0.poster }? Is that different than gp in gp.poster?

AsifHabib Over a year ago

Thanks, how to convert array of strings to array of objects?

Klevison · Accepted Answer · 2017-02-03 19:51:34Z

0

public struct GenrePosters: Decodable, Equatable{

    public let poster : String

    public init? (json: JSON) {

        guard let poster: String = "poster_path" <~~ json
            else {return nil}
        self.poster = poster
    }

    public static func ==(lhs: GenrePosters, rhs: GenrePosters) -> Bool {
        return lhs.poster == rhs.poster
    }
}

let genrePostersArray = [GenrePosters(poster: "one"), GenrePosters(poster: "two"), GenrePosters(poster: "three")]
let genrePostersStringArray = genrePostersArray.flatMap { $0.poster }
print(genrePostersStringArray) // ["one", "two", "three"]

answered Feb 3, 2017 at 19:51

Klevison

3,5142 gold badges22 silver badges35 bronze badges

1 Comment

Hamish Over a year ago

Note that flatMap(_:) is unnecessary here as the result of the transform is non-optional – you can simply use map(_:) instead.

Collectives™ on Stack Overflow

How to convert an array of custom objects to an array of strings?

2 Answers 2

2 Comments

1 Comment

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

2 Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Linked

Related