String

// STRINGS AS COLLECTIONS
let string = "Matt"
for char in string {
  print(char)
}

let stringLength = string.count
//let fourthChar = string[3]


// GRAPHEME CLUSTERS
let cafeNormal = "café"
let cafeCombining = "cafe\u{0301}"

cafeNormal.count
cafeCombining.count

cafeNormal.unicodeScalars.count
cafeCombining.unicodeScalars.count

for codePoint in cafeCombining.unicodeScalars {
  print(codePoint.value)
}


// INDEXING STRINGS
let firstIndex = cafeCombining.startIndex
let firstChar = cafeCombining[firstIndex]

//let lastIndex = cafeCombining
let lastIndex = cafeCombining.index(before: cafeCombining.endIndex)
let lastChar = cafeCombining[lastIndex]

let fourthIndex = cafeCombining.index(cafeCombining.startIndex, offsetBy: 3)
let fourthChar = cafeCombining[fourthIndex]

fourthChar.unicodeScalars.count
fourthChar.unicodeScalars.forEach { codePoint in
  print(codePoint.value)
}


// EQUALITY WITH COMBINING CHARACTERS
let equal = cafeNormal == cafeCombining


// STRINGS AS BIDIRECTIONAL COLLECTIONS
let name = "Matt"
let backwardsName = name.reversed()
let secondCharIndex = backwardsName.index(backwardsName.startIndex, offsetBy: 1)
let secondChar = backwardsName[secondCharIndex]

let backwardsNameString = String(backwardsName)


// SUBSTRINGS
let fullName = "Matt Galloway"
let spaceIndex = fullName.index(of: " ")!
let firstName = fullName[..<spaceIndex]
let lastName = fullName[fullName.index(after: spaceIndex)...]
let lastNameString = String(lastName)


// ENCODING
let char = "\u{00bd}"
for i in char.utf8 {
  print(i)
}

let characters = "+\u{00bd}\u{21e8}\u{1f643}"
for i in characters.utf8 {
  print("\(i) : \(String(i, radix: 2))")
}
for i in characters.utf16 {
  print("\(i) : \(String(i, radix: 2))")
}

let arrowIndex = characters.index(of: "\u{21e8}")!
characters[arrowIndex]

if let unicodeScalarsIndex = arrowIndex.samePosition(in: characters.unicodeScalars) {
  characters.unicodeScalars[unicodeScalarsIndex]
}

if let utf8Index = arrowIndex.samePosition(in: characters.utf8) {
  characters.utf8[utf8Index]
}

if let utf16Index = arrowIndex.samePosition(in: characters.utf16) {
  characters.utf16[utf16Index]
}