RinniSwift

var dict = ["blue": 2, "grey": 1, "purple": 4, "red": 2]

// subscript(key:)
dict["blue"]  // Optional(2)

// subscript(key:default:)
dict["grey", default: 0]  // 1

// subscript(position:)
if let ind = dict.firstIndex(where: { ($0.key == "red") }) {

RinniSwift

// 1. initializing dictionaries with the minimumCapacity(_:)
var someDict = Dictionary<String, Int>(minimumCapacity: 8)  
someDict.capacity  // 12

// 2. initializing dictionaries with unique key-value sequences
let newDict = Dictionary(uniqueKeysWithValues: zip(["one", "two", "three"], 1...3))
// ["two": 2, "three": 3, "one": 1]

// 3. initializing dictionaries with sequence of key-value tuples (drops duplicates)
let romanNumTuples = [("I", 1), ("V", 5), ("X", 10), ("L", 50), ("L", 44)]

RinniSwift

// 1. empty dictionary initialization
var numbers = Dictionary<String, Int>()
var newNumbers: Dictionary<String, Int> = Dictionary()

// 2. empty dictionary initialization using dictionary literals
var nums = [String: Int]()
var newNums: [String: Int] = [:]

// 3. predefininig elements with dictionary literals
var romanNumerals = ["I": 1, "V": 5, "X": 10, "L": 50]  // using type inference

RinniSwift

var numbers = Set<Int>(minimumCapacity: 30)
numbers.capacity  // 48

RinniSwift

var numbers = Set<Int>()

numbers.insert(3)   // (true, 3)
numbers.insert(22)  // (true, 22)
numbers.insert(22)  // (false, 22)

RinniSwift

// 1. empty set initialization
var numbers = Set<Int>()
var nums: Set<Int> = Set()

// 2. empty set initialization with array literal
var numbersSet: Set<Int> = []

// 3. creating set with predefined elements using array literals
var newNums: Set = [1, 2, 3, 4]

RinniSwift

class CircularBuffer<T> {
    
  var bufferMaxSize: Int
  var size = 0
  var elements = Array<T?>(repeating: nil, count: 8)

  var front: T? {
    if isEmpty() {
      return nil
    } else {

RinniSwift

func dequeue() -> T? {

  // ...

  // 1.
  if !isEmpty() {
    // 2.
    let front = elements[bufferMaxSize - size]
    elements[bufferMaxSize - size] = nil
    size -= 1

RinniSwift

class CircularBuffer<T> {

  // ...
  
  func enqueue(item: T) {
    
    // 1.
    if isEmpty() {
      elements[bufferMaxSize-1] = item
    } else {  

RinniSwift

class CircularBuffer<T> {

  // ...

  // 1.
  var front: T? {
    if isEmpty() {
      return nil
    } else {
      // 2.