// Playground - noun: a place where people can play
import UIKit
var str = "Hello, playground"
var str1="test"
str1
println("ddddd")
let implmentInteger : Double=12
let floattest:Float=4
//可变
func sumOf(numbers: Int...) -> Int {
var sum = 0
for number in numbers {
sum += number
}
return sum
}
sumOf()
sumOf(42, 597, 12)
var optionString:String?="Hello"
optionString=nil
var greeting="Hello!"
var optionName:String?="Jack"
optionName=nil
if let name=optionName{
greeting="Hello,\(name)"
}else{
greeting
}
struct Color {
let red = 0.0, green = 0.0, blue = 0.0
init(_ red: Double,_ green: Double,_ blue: Double) {
self.red = red
self.green = green
self.blue = blue
}
}
Color(1,1,1)
var description : String {
return "Hello"
}
description
let possibleNumber = "123"
let convertedNumber = possibleNumber.toInt()
// convertedNumber 被推测为类型 "Int?"， 或者类型 "optional Int"
convertedNumber!
数组
Array<SomeType>
SomeType[]
var shoppingList: String[] = ["Eggs", "Milk"]var shoppingList = ["Eggs", "Milk"]var someInts = Int[]()
someInts=[]var threeDoubles = Double[](count: 3, repeatedValue:0.0)
字典Dictionary<KeyType, ValueType>var airports: Dictionary<String, String> = ["TYO": "Tokyo", "DUB": "Dublin"]var airports = ["TYO": "Tokyo", "DUB": "Dublin"]var namesOfIntegers = Dictionary<Int, String>()namesOfIntegers = [:]
// namesOfIntegers 又成为了一个 Int, String类型的空字典