Swift - best way to handle a dictionary of dictionaries? - arrays

Question

I have an array of people that all have a list of favourite books.
Each book has several properties, such as book title, book description, book author.
What I want to do is create a dictionary of dictionaries to be able to access a specific person, and then access each book of that person and extract the book name, book title author etc from that that.
currently what I am doing is the declaring a dictionary like so:
var dictToHoldBooKValue = [String : [String : AnyObject]]()
the first String is the key, which I will create as the name of the person, the second pard is a dictionary, which will have a key of type string (which I will set as the book property name like "book Title" or "book author" and the any object is the value of that key.
example: I modify the dictionary like so:
dictToHoldBooKValue["Mark"] = ["book Title" : (bookTitle as? String)]
However, this approach does not seem to be working because "Mark" has several books he likes and so when I print the dict count it only shows one. Also, I have no idea how I would use this dict to to get at the book author property or any other property.
Anybody know a more elegant solution?
Thanks!

Answer 1

Make a struct to represent a book. Make it contain all the book attributes you want to track.
struct Book {
var title: String
var author: String
var year: Int
}
Your outer dictionary will be exactly as you described.
Your inner dictionary will have its key as the name of the book and it will contain Book structs.
var dictToHoldBooKValue = [String : [String : Book]]()
dictToHoldBooKValue["Mark"] = [
"You Only Live Twice" : Book("You Only Live Twice", "Ian Flemming", 1961),
"Casino Royale" : Book("Casino Royale", "Ian Flemming", 1959)
]
Access it like this:
print(dictToHoldBooKValue["Mark"]["You Only Live Twice"].author)
This is all fine if you are loading this data from somewhere and want to show it in a specific way. If you need to query data in a more flexible way, you should consider using CoreData.

Answer 2

If you want to use key-value coding, you can use typealiases to simplify your code:
typealias Book = [String: AnyObject]
typealias Books = [Book]
typealias Person = [String: AnyObject]
var people = [Person]()
var mark = Person()
var marksBooks = Books()
var theLittlePrince = [
"title" : "The Little Prince",
"author": "Antoine de Saint-Exupéry"
]
marksBooks.append(theLittlePrince)
mark["books"] = marksBooks
people.append(mark)
print(people)
Prints:
[["books": (
{
author = "Antoine de Saint-Exup\U00e9ry";
title = "The Little Prince";
}
)]]