Get widget index on Swift

Question

I’m trying to use the method index to know the index of an object within the array but do not know which parameter(s) to pass.

My code:

/// Struct that define the track model 
struct Track {
  let songID: Int
  let songName: String

  init(songID id: Int, songName name: String) {
    songID = id
    songName = name
  }
}

/// Struct that define the playlist model 
struct Playlist {
  var tracks = [Track]()
}

// MARK: - Exemplo
let s = Track(songID: 1, songName: "song1")
let t = Track(songID: 2, songName: "song2")
let u = Track(songID: 2, songName: "song3")
let v = Track(songID: 2, songName: "song4")

var playlist = Playlist.init(tracks: [s, t, u, v])

// se eu passar o objeto t da o seguinte erro: 
// Cannot convert value of type 'Track' to expected argument type '@noescape (Track) throws -> Bool'
if let index = playlist.tracks.indexOf(t){
  print(index)
}

Answer 1

You have to specify which property you want to compare, as in your example the only property with unique value is the name, I used it to compare.

if let index = playlist.tracks.indexOf({$0.songName == t.songName}){
  print(index)
}

Functional example: http://swiftstub.com/910951409