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

Why does my code not work?? Thanks

In the editor, you have a pretty complex dictionary representing a movie. It contains a nested dictionary, which itself contains an array of Strings as a value.

Your job is to assign the string containing the value for the lead actor (which for the sake of the example is at position 0 in the array) to the variable leadActor.

Since dictionaries return optional values, you will have to use an if let statement to unwrap each consecutive operation.

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

var leadActor: String = ""

// Enter code below

if let movieCast = movieDictionary["Spectre"], let mainActor = movieCast["cast"] {
  var leadActor = mainActor[0] 

} 

1 Answer

So close Mitchell! You're redeclaring leadActor variable inside the if let body - you just need to ditch the var before the leadActor for it to work.

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

var leadActor: String = ""

// Enter code below

if let movieCast = movieDictionary["Spectre"], let mainActor = movieCast["cast"] {
  var leadActor = mainActor[0] 

} 

So I dont need to mention the var again because I already declared it before, and redeclaring it is causing an error? Thanks!

Yeah, the thing is using var inside the context of the if let declares an entirely new variable with a new memory ref. So you just need to use leadActor as it's been declared before the if let 👍