swift学习记录

0.句末不用打分号

1.变量var 常量let，不用指定类型，自动推断

2.当需要指定类型时：

let explicitDouble:Double=7  //7.0

3.+号不能自动把数字变成string，全部用显式转换:

let label="The width is"

let width=94
let widthLable= label+String(width) 

4.也可以用\()来插入一个变量或常量,比java麻烦嘛。

let apples=3

let summary="I have \(apple) apples" // I have 3 apples

let oranges=5

let fruitSummary="I have  \(apple+oranges) pieces of fruit"//I have 8 pieces of fruit

5.数组和字典用[]，感觉跟groovy一样啊

var array=["catfish","water","tulips","blue paint"]

array[1]

array[1]="bottle of water"

var occupations = [

    "malcolm":"Captain",

    "Kaylee":"Mechanic",

]

occupations["Jayne"]="Public Relations" //改了一个值，这语法貌似是跟groovy的map一样的

occupations  //这个直接起到了打印效果，至少在playground里是

6.空的数组和字典，指定类型的

let emptyArrary=String[]()

let emptyDictionary = Dictionary<String,Float>()

7.空的数组和字典，不指定类型的

let shoppinglist=[]

let dictionary=[:]  //如果类型能推断出来才用这里的两种写法

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

import Cocoa
var myVariable=42

myVariable=50

let myConstant=42
let implicitInteger=70

let implicitDouble=70.0

let explicitDouble:Double=70
let explicitFloat:Float=4
let label="The width is "

let width = 94

let widthLabel=label + String(width)
let apples=3

let oranges=5

let appleSummary="I have \(apples) apples."

let fruitSummary="I have \(apples+oranges) piece of fruit"
let floatNumber:Float=4

let name="Ting"

let floatsummary="i am adding \(floatNumber+explicitFloat), haha \(name)"
var array=["catfish","water","tulips","blue paint"]

array[1]

array[1]="bottle of water"

var occupations = [

    "malcolm":"Captain",

    "Kaylee":"Mechanic",

]
occupations["Jayne"]="Public Relations"

occupations
let emptyArrary=String[]()

let emptyDictionary = Dictionary<String,Float>()
let shoppinglist=[]
let individualScores=[75,43,103,87,12]

var teamScore = 0

teamScore

for score in individualScores{

   "aaa"

    println(score)

}
"aaa"
for score in individualScores{

    if score > 50 {

        teamScore+=3

    } else {

        teamScore+=1

    }
}

teamScore
var optionalString:String? = "Hello"

optionalString == nil
var optionalName:String? = "John Appleseed"
var greeting = "Hello!"

if let name = optionalName{

    greeting = "Hello, \(name)"

} else if optionalName == nil {
greeting = "Hello, nil"

}
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."

}

swift学习记录