SwiftDemo for String and characters.

swiftDemo.playground

//: Playground - noun: a place where people can play

import UIKit
// increment operator
var i = 1
i++
i
i = 1
++i
i

// comparison of string
let a = NSObject()
let b = NSObject()
let c = a
a === b
a === c

// range operators
for index in 1...5 {
    index
}

// Characters
for char in "Dog"{
    print(char)
}

let chars: [Character] = ["C", "a", "t"]
let charsString = String(chars)

// unicode scalars
var str = "\u{1F425}"

let message = "\"Hello World\""

// extend grapheme clusters
let eAcute: Character = "\u{E9}"
let combinedEAcute: Character = "\u{65}\u{301}"

let precomposed: Character = "\u{D55C}"
let c1 = "\u{1112}"
let c2 = "\u{1161}"
let c3 = "\u{11AB}"
let decomposed = "\(c1)\(c2)\(c3)"

// counting characters
var word = "cafe"
count(word)
word += "\u{301}"
count(word)

// accessing string
let greeting = "Guten Tag"
let startIndex = greeting.startIndex
let endIndex = greeting.endIndex
greeting[startIndex]
greeting[startIndex.successor()]
greeting[endIndex.predecessor()]
let index = advance(greeting.startIndex, 7)
greeting[index]

for index in indices(greeting) {
	greeting[index]
}

// inserting and removing
var welcome = "hello"
welcome.insert("!", atIndex: welcome.endIndex)
welcome.splice(" there", atIndex: welcome.endIndex.predecessor())
welcome.removeAtIndex(welcome.endIndex.predecessor())
welcome = "hello there"
let range = advance(welcome.endIndex, -6) ..< welcome.endIndex
welcome.removeRange(range)


// comapring strings
let quotation = "haha"
let sameQuotation = "haha"
quotation == sameQuotation

let eAcuteQuestion = "Voulez-vous un caf\u{E9}?"
let combinedEAcuteQuestion = "Voulez-vous un caf\u{65}\u{301}?"
eAcuteQuestion == combinedEAcuteQuestion

let latinCapitalLetterA: Character = "\u{41}"
let cyrillicCapitalLetterA: Character = "\u{0410}"
latinCapitalLetterA == cyrillicCapitalLetterA

// prefix and suffix equality
var testArray = [String]()
for index in 0..<10 {
	testArray.append("Header\(index) \(index)Tailer")
}

var headerCount = 0
var tailerCount = 0
for message in testArray {
	if message.hasPrefix("Header") {
		++headerCount
	}
	if message.hasSuffix("Tailer") {
		++tailerCount
	}
}
headerCount
tailerCount

// Unicode Representations of Strings
let dogString = "Dog!!\u{1F436}"
var resultForUTF8 = [UInt8]()
for codeUnit in dogString.utf8 {
	resultForUTF8.append(codeUnit)
}
resultForUTF8

var resultForUTF16 = [UInt16]()
for codeUnit in dogString.utf16 {
	resultForUTF16.append(codeUnit)
}
resultForUTF16

var resultForUnicodeScalars = [UnicodeScalar]()
for codeUnit in dogString.unicodeScalars {
	resultForUnicodeScalars.append(codeUnit)
}
resultForUnicodeScalars