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iOS Swift 2.0 Enumerations and Optionals Introduction to Optionals Nil Values in Collections

Posted by Matt Conway
Matt Conway
1,572 Points

if let statement

Not sure why this is not working

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.

/Users/mattconway/Desktop/Screen Shot 2016-03-10 at 1.04.36 PM.png

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

var leadActor: String = ""

// Enter code below
let leadActor = movieDictionary[0]
if let movie = movieDirectory["Spectre"], let cast = movie["cast"], let ledActor = cast[0] {
print("Spectre")
}

1 Answer

Paul Brazell
Paul Brazell
14,371 Points
Paul Brazell
Paul Brazell
14,371 Points

Couple of things. You have a typo in your If/let statement for movieDictionary. You called it movieDirectory.

You cannot have let ledActor = cast[0] in your if let chain because cast[0] does not produce an optional value.

It doesn't ask you to print anything, you are just assigning to value of cast[0] to the variable leadActor.

Here is the result.

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

var leadActor = ""

// Enter code below

if let movie = movieDictionary["Spectre"], let cast = movie["cast"]{
    leadActor = cast[0]
}