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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 isn't working

Challenge Task 1 of 1

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 2016-03-09 at 5.09.58 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
if let leadActor = movieDictionary["0"] {
  print(leadActor)
  }

3 Answers

Matt Conway
Matt Conway
1,572 Points
Matt Conway
Matt Conway
1,572 Points

Still doesn't work. See if you can view it at this Google Drive link.

https://drive.google.com/file/d/0BxI6Cu9E-CnqYzg3eXpjdDVJXzg/view?usp=sharing

Jhoan Arango
Jhoan Arango
14,575 Points
Jhoan Arango
Jhoan Arango
14,575 Points

Hey Matt: I gave you part of the answer.. You forgot to finish the rest of the challenge, which is to add the lead actor to the variable. 

if let movie = movieDictionary["Spectre"], let cast = movie["cast"], let leadActor = cast[0] {
self.leadActor = leadActor
}
Daniel Williams
Daniel Williams
19,746 Points
Daniel Williams
Daniel Williams
19,746 Points

The answer that worked for me was slightly different;

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

Jhoan Arango
Jhoan Arango
14,575 Points
Jhoan Arango
Jhoan Arango
14,575 Points

Hello,

What you are doing is calling a dictionary as you would call an array. 

// Calling a dictionary 

let value = Dictionary["Key"]

// Callin an array 

let value = Array[0]

So in this case you have to access 2 dictionaries before getting to the array. So the if let statement should be chain a bit longer.

something like:

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

Hope this helps..

Good luck