playground_trial

playground_trial.swift

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

import UIKit

var str = "Hello, playground"

/** constant & value **/
let const = 10
//const = 15 //error
var value = 20
value = 25

/** type inference **/
let lastName = "Nanashima" // String
let age = 32                    // Int
let height = 169.5              // Double
let isMale = true               // Boolean

let info = lastName + String(age)   // Values are never implicitly converted another type.
let info2 = "He is \(height) cm tall."  // Include values in strings.

/** type annotation **/
let firstName:String = "Hideyuki"
let weight:Float = 75

/** array & dictionary **/
var array = [1,2,3,4]
array[2]
array[2] = 5

var dictionary = ["Japan":"Tokyo", "France":"Paris"]
dictionary["Japan"] = "Kyoto"

/** tuple **/
let tuple = (32, "Nanashima")
tuple.0
tuple.1

/** optionals **/
var optionalTitle:String? = "Mr."
optionalTitle = nil
//str = nil //error

/** if **/
var name:String
if let title = optionalTitle {
    name = title + lastName
}else{
    name = "Guest"
}

/** switch **/
// no need to explicitly break
// error without default in this case
let vegetable = "red pepper"
switch vegetable {
case "celery":
    let vegetableComment = "Add some raisins and make ants on a log."
case "cucumber", "watercress":
    let vegetableComment = "That would make a good tea sandwich."
case let x where x.hasSuffix("pepper"):
    let vegetableComment = "Is it a spicy \(x)?"
default:
    let vegetableComment = "Everything tastes good in soup."
}

/** loop **/
var n = 2
while n < 100 {
    n = n * 2
}
n

var m = 2
do {
    m = m * 2
} while m < 100
m

var num = 0
for var i=0; i<5; i++ {
    num++
}

for _ in 1..<5 {
    num++
}

for _ in 1...5 {
    num++
}

let names = ["taro", "jirou", "saburo"]
for name in names {
    name
}

let radius = 10.0
for circleProp in 1...100 {
    let alpha = Double(circleProp) / 100.0 * 2.0 * M_PI
    let y = radius * (1 - cos(alpha))
    let x = radius * (alpha - sin(alpha))
}

let citDict = ["Japan":"Tokyo", "France":"Paris"]
for (country, city) in citDict {
    city
    country
}

/** functions **/
func sum(first:Int, second:Int = 0) -> Int{
    return first + second
}
sum(1, second:2)
sum(1)

func calculateStatistics(scores: Int...) -> (min: Int, max: Int, avg: Int) {
    var min = scores[0]
    var max = scores[0]
    var avg = 0
    
    for score in scores {
        if score > max {
            max = score
        } else if score < min {
            min = score
        }
        avg += score / scores.count
    }
    
    return (min, max, avg)
}
let result = calculateStatistics(5, 3, 100, 3, 9)
result.avg
result.2

// nested function, first-class type, closure

/** class **/
class Person {
    
    var name:String? = nil
    var age = 0
    
    init(name:String, age:Int){
        self.name = name
        self.age = age
    }
    
    func whoAmI() -> String {
        return "I am \(name!), \(age) years old"
    }
}

var nanashima = Person(name: "Nanashima", age:32)
nanashima.whoAmI()

// computed property & property observers
class Engeneer : Person {
    
    var workingHours:Int{
        get{
            return self.workingHours + 4
        }
        set{
            self.workingHours = newValue
        }
    }
    var salary:Int = 0{
        willSet{
            // You can use `newValue`
        }
        didSet{
            // You can use `oldValue`
        }
    }
    
    override func whoAmI() -> String {
        return super.whoAmI() + "and working \(workingHours) hours"
    }
}

// enum, struct

// protocol, extension

// generics

// UIKit
let frame = CGRectMake(0, 0, 300, 100)

let view = UIView(frame: CGRectMake(0, 0, 320, 568))
view.backgroundColor = UIColor.grayColor()
let label = UILabel(frame: frame)
label.text = "Hello playground"
view.addSubview(label)

var imageURL:NSURL = NSURL(string: "http://goo.gl/ys7ACa")!
let imageData:NSData = NSData(contentsOfURL: imageURL)!
let image = UIImage(data: imageData)

let imageView = UIImageView(image:image)

imageView.center = CGPoint(x:150, y:300)

view.addSubview(imageView)