- 我们来回顾Swift的基础知识, 然后下篇文章我会慢慢的把流行的Swift开源库介绍给你们。
- new Project -> new PlayGround
import UIKit
4
5 // HelloWorld
6 var str = "Hello, playground"
7
8 // 常量可以改变值
9 var myVariable = 42
10 myVariable = 50
11 let myConstant = 42
12
13 // 指定数据类型
14 let floatNumber:Float = 4
15
16 // 使用强制转换
17 let lable = "the lable is "
18 let width = 94
19 let labelwidth = lable + String(width)
20
21 // 使用双引号中的\来转换
22 let apples = 3
23 let oranges = 5
24 let appleSummary = "i have \(apples) apples"
25 let orangeSummary = "i have \(oranges) oranges"
26
27 // 自动识别数据类型加斜杠转换
28 let somebody = "Alice"
29 let age = 23.5
30 let hellosomebody = "\(somebody) is \(age)"
31
32 // 数组的初始化以及赋值
33 var shoppingList = ["Alice", "Dylan"]
34 shoppingList[1] = "Petit Alice"
35
36 // 字典的初始化以及赋值
37 var occupations = [
38
39 "male" : "Alice",
40 "female" : "Dylan"
41 ]
42 occupations["male"] = "Alice.Petit"
43
44 // 初始化一个空的数组或者字典
45 let emptyArray = [String]()
46 let emptyDictionary = [String:Float]()
47
48 // 初始化一个自动识别类型的字典或者数组
49 let emptyArray_auto = []
50 let emptyDictionary_auto = [:]
51
52 // 控制流 不能省略大括号
53 let individualScores = [75, 42, 103, 87, 12]
54 var teamScore = 0
55 for score in individualScores {
56 if score > 50 {
57 teamScore += 3
58 } else {
59 teamScore += 1
60 }
61 }
62 teamScore
63
64 // 写到这里 突然发现 变量名称直接打出去 就能打印了
65 let emptyA = ["key": "value"]
66 emptyA
67
68 // 在if条件中 条件必须是bool表达式 输如一个直接score会出错的 看好了 是必须是表达式
69
70 // 使用let来标记
71 var optionalString: String? = "Hello"
72 optionalString == nil
73
74 var optionalName: String? = "John Appleseed"
75 var getting = "Hello"
76 optionalName = nil
77
78 if let name = optionalName {
79 getting = "hello, \(name)"
80 } else {
81 getting = "hello, Alice"
82 }
83
84 // switch
85 let vegetable = "red pepper"
86 switch vegetable {
87 case "celery":
88 let vegetableComment = "add some"
89 case "cummber", "watercress":
90 let vegetableComment = "this would make a good tea"
91 case let x where x.hasSuffix("pepper"):
92 let vegetableComment = "is it a spicy \(x)"
93 default:
94 let vegetableComment = "everything tastes good in soup"
95 }
96
97 // 碰到匹配的句子后 switch不会在继续往前走
98 let interstingNumbers = [
99 "prime" : [2, 3, 4, 6],
100 "Fibonacci" : [1, 1, 2, 3],
101 "Square" : [1, 4, 5]
102 ]
103
104 var largest = 0
105 var maxtype = ""
106 for (kind, numbers) in interstingNumbers {
107
108 for number in numbers {
109 if number > largest {
110 largest = number
111 maxtype = kind
112 }
113 }
114
115 }
116 largest
117 maxtype
118
119 // while
120 var n = 2
121 while n < 100 {
122 n = n*2
123 }
124 n
125
126 var m = 2
127 do {
128 m = m*2
129 } while m < 100
130
131 m
132
133 // 注意到了把 while do 不会多循环一次的 他们是等价的
134
135 // ..<
136 var firstForLoop = 0
137 for i in 0..<4 {
138 firstForLoop += i
139 }
140 firstForLoop
141
142 var secondForLoop = 0
143 for var i=0; i<4; i++ {
144 secondForLoop += i
145 }
146 secondForLoop
147
148 var thirdForLoop = 0
149 for i in 0...4 {
150 thirdForLoop += i
151 }
152 thirdForLoop
153
154 // func
155 func greet(name:String, day:String) ->String {
156
157 return "Hello. \(name), today is \(day)"
158 }
159 greet("Alice", "Tuesday")
160
161 func whateating(name:String) ->String {
162 return "\(name) eat what?"
163 }
164 whateating("Alice")
165
166 // 使用元组让一个函数返回多个值
167 func calculateStatistics(scores:[Int]) ->(min: Int, max:Int, sum:Int) {
168 var min = scores[0]
169 var max = scores[0]
170 var sum = 0
171
172 for score in scores {
173
174 if score > max {
175 max = score
176 }
177
178 if score < min {
179 min = score
180 }
181
182 sum += score
183 }
184
185 return (min, max, sum)
186 }
187 let staticArray = [1, 2, 3, 4, 5]
188 calculateStatistics(staticArray)
189 // 返回值可以用点语法单独的取到 也可以用位置
190 calculateStatistics(staticArray).sum
191 calculateStatistics(staticArray).0
192
193 // 函数可以带有可变个数的参数
194 func sumOf(numbers: Int...) ->Int {
195
196 var sum = 0
197 for number in numbers {
198 sum += number
199 }
200 return sum
201 }
202 sumOf(1, 2)
203 sumOf()
204 sumOf(1,2 ,3 ,4,5)
205
206 // 计算参数平均值的联系
207 func acr(number:Int...) ->Float {
208
209 var sum = 0
210 for num in number {
211 sum += num
212 }
213 return Float(sum)/Float(number.count)
214 }
215 acr(1, 2, 3)
216 acr(3, 4)
217
218 // 函数可以嵌套 被嵌套的函数可以访问外侧函数的变量 可以嵌套函数来重构一个太长或者太复杂的函数
219 func returnFifteen() ->Int {
220 var y = 10
221 func add() {
222 y += 5
223 }
224 add()
225 return y
226 }
227 returnFifteen()
228
229 // 函数可以作为另一个函数的返回值
230 func makeIncrementer() ->(Int->Int) {
231
232 func addOne(number: Int) ->Int {
233 return 1 + number
234 }
235 return addOne
236 }
237
238 var increment = makeIncrementer()
239 increment(7)
240
241 // 函数可以当做参数 传入另一个函数
242 func hasAnymatches(list:[Int], condition:Int->Bool) ->Bool {
243
244 for item in list {
245 if condition(item) {
246 return true
247 }
248 }
249 return false
250 }
251
252 func lessThanTen(number: Int) ->Bool {
253 return number < 10
254 }
255
256 var numbers = [20, 19, 2, 12]
257 hasAnymatches(numbers, lessThanTen)
258
259 // 函数实际上是一特殊的闭包 使用{} 来创建一个匿名的闭包 使用int将参数和饭追只类型声明与闭包函数体进行分离
260 numbers.map({
261 (number: Int) -> Int in
262 let result = 3 * number
263 return result
264 })
265
266 numbers.map({
267 (number: Int) -> Int in
268 if number % 2 != 0 {
269 return 0
270 }
271 return 1
272 })
273
274 let mappedNumbers = numbers.map({
275 number in 3 * number
276 })
277 mappedNumbers
278
279 let sortedNumbers = sorted(numbers) {
280 $0 > $1
281 }
282 sortedNumbers
283
284 // 对象和类
285 class Shape {
286 var numberOdSides = 0
287 let testGetNumber = 0
288
289 func setNumber(number: Int) {
290 numberOdSides = number
291 }
292
293 func simpleDescription() ->String {
294
295 return "A shape with \(numberOdSides) sides"
296 }
297 }
298
299 var shape = Shape()
300 shape .setNumber(10)
301 shape .simpleDescription()
302
303 // init
304 class NamedShape {
305 var numberOfSides: Int = 0
306 var name:String
307
308 init(name: String, number:Int) {
309 self.name = name
310 self.numberOfSides = number
311 }
312
313 func simepleDescription() ->String {
314 return "A \(name) with \(numberOfSides) sides"
315 }
316 }
317 var nameShape = NamedShape(name: "Alice", number: 20)
318 nameShape .simepleDescription()
319
320 // 继承
321 class Square: NamedShape {
322 var sidelength: Double
323
324 init(sidelength: Double, name:String, number: Int) {
325
326 self.sidelength = sidelength
327 super.init(name: name, number: number)
328 }
329
330 func area() ->Double {
331
332 return sidelength * sidelength
333 }
334
335 override func simepleDescription() -> String {
336 return "a Square with Sides of Length \(sidelength)"
337 }
338 }
339
340 // getter setter
341 class EquilaterTrabgle: NamedShape {
342
343 var sideLengths: Double = 0.0
344
345 init(side: Double, name: String, number: Int) {
346 self.sideLengths = side
347 super.init(name: name, number: number)
348 }
349
350 var perimeter: Double {
351
352 get {
353 return 3 * sideLengths
354 }
355
356 set {
357 sideLengths = newValue / 3.0
358 }
359 }
360
361 override func simepleDescription() -> String {
362 return "an square triagle with \(sideLengths)"
363 }
364 }
365
366 var triangle = EquilaterTrabgle(side: 3.1, name: "Alice", number: 3)
367 triangle.perimeter
368 triangle.perimeter = 9.9
369 triangle.sideLengths
370 triangle.simepleDescription()
371
372 // 默认的情况相爱 方法的参数名和他们在方法内部的名字一样
373 class counter {
374 var count: Int = 0
375 func incrementBy(amount: Int, numberOfTimes times: Int) {
376 count += amount * times
377 }
378 }
379 var count = counter();
380 count.incrementBy(2, numberOfTimes: 7)
381
382 // 处理变量的可选值的时候。 你可以在操作之前加？之前的值是nil的话那么后边的东西讲不会被执行 否则 ？后边的东西被运行 这种情况下 整个表达式只有一个可选值
383 let optionalSquare: Square = Square(sidelength: 2, name: "Alice", number: 3)
384 let sidelength = optionalSquare.sidelength
385
386 // 枚举和结构体
387 enum Rank: Int {
388
389 case Ace = 1
390 case Two, Three, Four, Five
391 case Jack, Queen
392
393 func simpleDescription() ->String {
394 switch self {
395 case .Ace:
396 return "ace"
397 case .Jack:
398 return "jack"
399 case .Queen:
400 return "queen"
401 default:
402 return String(self.toRaw())
403 }
404 }
405 }
406 let ace = Rank.Ace
407 let aceRowValue = ace.toRaw()
408 ace.simpleDescription()
409
410 // 写一个函数 来比较两个Rank值
411 enum Ranks: Int {
412 case one = 1
413 case two = 2
414 case three = 3
415
416 func sub(number1: Int, number2: Int) ->Int {
417
418 return number1 > number2 ? number1 : number2
419 }
420 }
421 let one = Ranks.one
422 one.sub(10, number2: 2)
423
424 // 使用toRow 和fromRow函数在原始值和枚举值之前轻松的切换
425 if let convertedRank = Rank.fromRaw(3) {
426 let threeDescription = convertedRank.simpleDescription()
427 threeDescription
428 }
429
430 // 枚举的成员是实际值并不是原始值的另一种表达方法 实际上 如果原始值没有意义 你不需要设置
431 enum Suit {
432
433 case Spades, Hearts, Diamonds, Clubs
434
435 func simleDescription() -> String {
436 switch self {
437 case .Spades:
438 return "spa"
439 case .hearts:
440 return "heart"
441 case .Diamonds:
442 return "dia"
443 case .Clubs:
444 return "clubs"
445 }
446 }
447 }
448 let hearts = Suit.Hearts
449 let heartsDescription = hearts.simleDescription()
450
451 // 定义一个结构体 接受上边传来的东西
452 struct Card {
453 var rank: Rank
454 var suit: Suit
455
456 func sipleDescription() ->String {
457 return "\(rank), \(suit)"
458 }
459 }
460 let thspeed = Card(rank: .Three, suit: .Spades)
461 let thspeeds = thspeed.sipleDescription()
462 thspeeds
463 thspeed
464
465 // 通过枚举 区别正确或者错误信息
466 enum ServerResponse {
467 case Result(String, String)
468 case Error(String)
469 }
470
471 let success = ServerResponse.Result("Alice", "Dylan")
472 let failure = ServerResponse.Error("Error")
473
474 switch success {
475 case let .Result(sunrise, sunset):
476 let serverResponse = "\(sunrise), \(sunset)"
477 case let .Error(error):
478 let serverResponse = "Failure .. \(error)"
479 }
480
481 // 协议和扩展
482
483 // 首先 使用protocal来申明一个协议
484 protocol ExamplepRrotocol {
485 var simpleDescription: String {
486 get
487 }
488 mutating func adjust()
489 }
490
491 // 类 枚举 结构体都可以实现协议
492 class SimoleClass: ExamplepRrotocol {
493 var simpleDescription: String = "A very petit girl"
494 var anotherpRroperty: Int = 69105
495 func adjust() {
496 simpleDescription += "Alice"
497 }
498 }
499
500 var a = SimoleClass()
501 a.adjust()
502
503 let aDescription = a.simpleDescription
504
505 struct SimpleStructure : ExamplepRrotocol{
506 var simpleDescription: String = "Alice"
507 mutating func adjust() {
508 simpleDescription += ".Dylan"
509 }
510 }
511
512 var b = SimpleStructure()
513 b.adjust()
514 let bDescription = b.simpleDescription
515
516 // extension 为现有的类型添加功能
517 //extension Int: ExamplepRrotocol {
518 // var simpleDescription: String {
519 // return "the number \(self)"
520 // }
521 //}
网友评论