Learning Exercise
Tuples are used to combine multiple values into a single compound value where each of the values may have a different type. The compound value has a type that is the combination of the individual values' types.
let order: (String, Double, Int) = ("biscuits", 2.99, 3)
The individual items of a tuple may be accessed by appending a .n to the tuple's name where n is the index of the element you would like to access, starting with 0.
let orderItem = order.0
// => "biscuits"
let orderQuantity = order.2
// => 3
The components of a tuple may also be accessed through decomposition:
let (teamName, wins, losses, draws) = ("Loons", 15, 11, 8)
let points = 3 * wins + draws
// => 53
Unneeded values can be ignored in decomposition by using an _ in place of a name:
let (_, wins, _, draws) = ("Loons", 15, 11, 8)
let points = 3 * wins + draws
// => 53
You can provide more semantic information about a tuple by supplying labels to the components of a tuple. The individual elements can then be accessed by either their index or their label:
let cindy: (name: String, age: Int) = (name: "Cindy", 28)
let cindyName = cindy.name
// => "Cindy"
let cindyAge = cindy.1
// => 28
You are an elf working in Santa Claus' logistics division and you have been given a pair of tasks from the boss for upgrading the system's software.
Your first task is updating the complex number array that helps run Santa's sleigh. The boss discovered that the last development team stored the arrays using Cartesian coordinates rather than polar coordinates, which everyone knows are the boss' favorite.
For this task you will need to implement the function cartesianToPolar(_:) that takes in a tuple, (x: Double, y: Double), and return a new tuple, (r: Double, phi: Double), where:
See this image for an example
Attribution: https://en.wikipedia.org/
let coordinate = (x: -78.70524308742053, y: -39.243573777212724)
cartesianToPolar(coordinate)
// => (r: 87.94642330565522, phi: -2.6790540755626306)
For your second task, your boss is upgrading its database and is modifying its record structures. They want to combine the records from the toy production database and the toy recipient databases to save space and give the product leads better visibility into the demand for their toy.
For this task you will implement the function combineRecords(production:gifts:) that takes two tuples as input, production: (toy: String, id: Int, productLead: String) and gifts: (Int, [String]) and your function will return a combined tuple, (id: Int, toy: String, productLead: String, recipients: [String]). Note that the two id fields in the input tuples are guaranteed to be the same value.
combineRecords(
production: (
toy: "Chemistry set",
id: 328509,
productLead: "Binkles"
),
gifts: (
328509,
["Inés", "Maxime", "Bandile", "Shaurya", "Екатерина"]
)
)
// => (id: 328509, toy: "Chemistry set", productLead: "Binkles", recipients: ["Inés", "Maxime", "Bandile", "Shaurya", "Екатерина"])
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