kamwysoc

struct Car: Decodable {
    let manufacturer: String
    let model: String
}

struct Person: Decodable {
    let name: String
    let lastName: String
}

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let names = ["John", "Paul", "Peter", "Tim"]
let shuffledNames = names.shuffled() // returns an array of names in shuffled order.

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let emptyCollection : [String] = []
emptyCollection.randomElement() // retuns nil

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let names = ["John", "Paul", "Peter", "Tim"]
names.randomElement()! 

let playerNumberToName : [Int: String] = [9: "Lewandowski", 7: "Ronaldo"]
playerNumberToName.randomElement()! 

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let randomIntFrom0To20 = Int.random(in: 0 ..< 20)
let randomFloat = Float.random(in: 0 ..< 1)

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let randomIntFrom1to10 = 1 + (arc4random() % 10) // return random number is the 1...6

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struct City: Hashable {
    let name : String
    let state : String
    let population : String
}
extension City : Hashable {
    func hash(into hasher: inout Hasher) {
        name.hash(into: &hasher)
        state.hash(into: &hasher)
    }

kamwysoc

var isTheWeatherNice : Bool = true
print(isTheWeatherNice) // prints true
//now it's starts to rain
isTheWeatherNice.toggle() // it will change the bool value.
print(isTheWeatherNice) // prints false

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let s: Set<[Int?]> = [[1, nil, 2], [3, 4], [5, nil, nil]]
s.contains([1,nil,2]) // returns true

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let arrayOfArrays = [[1,2],[3,4],[5,6]]

arrayOfArrays.contains([1,2]) // return false in Swift 4.1

arrayOfArrays.contains([1,2]) // now it returns True because of fact that the elements in the array conforms to Equatable protocol