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iOS Enumerations and Optionals in Swift Introduction to Optionals Nil Values in Collections

Aryaman Dhingra
Aryaman Dhingra
3,536 Points
Posted by Aryaman Dhingra
Aryaman Dhingra
3,536 Points

How to get optional values from nested dictionaries?

I don't understand optional values very well, I just need some clarification on how to get optional values from the nested dictionaries. I would also like to know what I am doing wrong.

optionals.swift 
let movieDictionary = ["Spectre": ["cast": ["Daniel Craig", "Christoph Waltz", "LÊa Seydoux", "Ralph Fiennes", "Monica Bellucci", "Naomie Harris"]]]

var leadActor: String = ""

// Enter code below

if let movieCast = movieDictionary["Spectre"], let movieFullCast = movieCast["cast"] {
  print(movieFullCast[0])
  }

2 Answers

tromben98
tromben98
13,273 Points
tromben98
tromben98
13,273 Points

Hi!

You are just printing the lead actor instad of assigning it to the leadActor property.

Here is the solution: 

let movieDictionary = ["Spectre": ["cast": ["Daniel Craig", "Christoph Waltz", "LÊa Seydoux", "Ralph Fiennes", "Monica Bellucci", "Naomie Harris"]]]

var leadActor: String = ""

// Enter code below
if let movie = movieDictionary["Spectre"],
let cast = movie["cast"] {
leadActor = cast[0]
}
Daniel Walkowski
Daniel Walkowski
549 Points
Daniel Walkowski
Daniel Walkowski
549 Points

You are not checking for the implicit optionals. All dictionaries and Arrays contain Optional keys/elements. If I am incorrect, please enlighten me.
I'd like to see an optional chaining solution. I'm trying to write one now