1.函數(shù)的定義與使用
//求兩個(gè)數(shù)之和的函數(shù)
//函數(shù)定義
//格式:func 函數(shù)名 （形參列表） -> 返回值類(lèi)型 { 函數(shù)體}
func sum (number1:Int, number2:Int) -> Int{
return number1 + number2;
}
//函數(shù)的使用
let sumTwoNubmer = sum(2, number2: 3);
2.函數(shù)的形參的注意點(diǎn)
2.1默認(rèn)形參是常量,若要在函數(shù)中對(duì)形參改變,在形參前加上var修飾
2.2給參數(shù)添加一個(gè)名字,調(diào)用函數(shù)的時(shí)候就一目了然
func sum (numberone number1:Int,numbertwo number2:Int) ->Int {
return number1 + number2;
}
let sum1 = sum(numberone: 1, numbertwo: 3)
print(sum1)
2.3形參的址傳遞:用inout 修飾形參,調(diào)用的時(shí)候用&
func test1 (inout number: Int) -> Int {
number++
return number;
}
var addtestNumber = 10;
let addnum = test1(&addtestNumber); //結(jié)果:11
print(addnum) //結(jié)果:11
print(addtestNumber) //結(jié)果:11
2.4不定參數(shù)函數(shù)
說(shuō)明:形參的個(gè)數(shù)是不定的，但是形參的類(lèi)型必須是相同的,不定個(gè)數(shù)的形參實(shí)際上是一個(gè)數(shù)組
1451876890323984.png
2.5默認(rèn)形參:每個(gè)參數(shù)都是有名字的,調(diào)用函數(shù)的時(shí)候,可以給任意一個(gè)參數(shù)賦值,其他的就去默認(rèn)值
func love (name1:String = "山伯",name2: String = "英臺(tái)") {
print("\(name1) love \(name2)")
}
love()
love("梁山伯")
love("梁山伯", name2: "祝英臺(tái)")
3.函數(shù)類(lèi)型:如果幾個(gè)函數(shù)參數(shù)列表相同以及返回值類(lèi)型相同，那么這兩個(gè)函數(shù)就有著相同的函數(shù)類(lèi)型。
//定義枚舉
enum Type: Int{
case jia = 0
case cheng
}
//3.函數(shù)類(lèi)型
func jia (n1: Int,n2: Int) -> Int{
return n1 + n2;
}
func cheng (n1: Int,n2: Int) -> Int{
return n1 * n2;
}
func typeName(type:Type) -> ((Int,Int) -> Int) {
var myfunc: (Int,Int) -> Int
switch type {
case .jia:
myfunc = jia
case .cheng:
myfunc = cheng
}
return myfunc
}
var myfunc: (Int,Int) -> Int
myfunc = typeName(Type.cheng)
print(myfunc(1,2))
myfunc = typeName(Type.jia)
print(myfunc(1,2))
4.函數(shù)嵌套
func typeName(type:Type) -> ((Int,Int) -> Int) {
func jia (n1: Int,n2: Int) -> Int{
return n1 + n2;
}
func cheng (n1: Int,n2: Int) -> Int{
return n1 * n2;
}
var myfunc: (Int,Int) -> Int
switch type {
case .jia:
myfunc = jia
case .cheng:
myfunc = cheng
}
return myfunc
}
5.閉包:等同于OC中的block
5.1定義
var myCloure0:((Int, Int) -> Int)?
//或者
typealias MyClosureType = (Int, Int) -> Int
var myCloure:MyClosureType?
5.2應(yīng)用
說(shuō)明:A控制器有兩個(gè)控件,Lable和按鈕,B控制器有三個(gè)控件,textfield和倆按鈕,點(diǎn)擊A按鈕進(jìn)入B控制器,在B控制的textfield中輸入字符串,點(diǎn)擊確定按鈕把textfield中的字符串在A控制器的lable中顯示,或者點(diǎn)擊返回按鈕直接返回
//A控制器--ViewController
// Created by Vanessa on 16/3/29.
// Copyright ? 2016年 Vanessa. All rights reserved.
//
import UIKit
class ViewController: UIViewController {
var showLable: UILabel?
var pushBtn: UIButton?
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
//1. 添加lable控件
showLable = UILabel.init(frame: CGRectMake((UIScreen.mainScreen().bounds.size.width - 200) * 0.5, 100, 200, 44))
showLable?.backgroundColor = UIColor.blueColor()
self.view.addSubview(showLable!)
//2. 添加按鈕控件
pushBtn = UIButton.init(type: UIButtonType.Custom)
pushBtn?.frame = CGRectMake((UIScreen.mainScreen().bounds.size.width - 200) * 0.5, 200, 200, 44)
pushBtn?.backgroundColor = UIColor.grayColor()
pushBtn?.setTitle("跳轉(zhuǎn)到下一界面", forState: UIControlState.Normal)
pushBtn?.titleLabel?.textColor = UIColor.whiteColor()
pushBtn?.addTarget(self, action: Selector.init(stringLiteral: "pushToSectionVC"), forControlEvents: UIControlEvents.TouchUpInside)
self.view.addSubview(pushBtn!)
// self.view.backgroundColor = UIColor.redColor()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
//MARK: - event
func pushToSectionVC() {
let secVC: SecondViewController = SecondViewController()
secVC.setMyblock {(str: String) -> Void in
self.showLable?.text = str
}
self.presentViewController(secVC, animated:true, completion: nil)
}
}
//B控制器--SecondViewController
import UIKit
class SecondViewController: UIViewController {
var myBlock: ((str:String) -> Void)?
var textField: UITextField?
var backBtn: UIButton?
var sureBtn: UIButton?
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
self.view.backgroundColor = UIColor.whiteColor()
textField = UITextField.init(frame: CGRectMake((UIScreen.mainScreen().bounds.size.width - 100) * 0.5, 100, 100, 44))
textField?.backgroundColor = UIColor.greenColor()
self.view.addSubview(textField!)
backBtn = UIButton.init(frame: CGRectMake(50, 200, 60, 40))
backBtn?.setTitle("返回", forState: UIControlState.Normal)
backBtn?.backgroundColor = UIColor.blueColor()
backBtn?.addTarget(self, action: Selector.init(stringLiteral: "back"), forControlEvents: UIControlEvents.TouchUpInside)
self.view.addSubview(backBtn!)
sureBtn = UIButton.init(frame: CGRectMake(200, 200, 60, 40))
sureBtn?.setTitle("確定", forState: UIControlState.Normal)
sureBtn?.backgroundColor = UIColor.blueColor()
sureBtn?.addTarget(self, action: Selector.init(stringLiteral: "sure"), forControlEvents: UIControlEvents.TouchUpInside)
self.view.addSubview(sureBtn!)
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
func setMyblock(tempBlock: (str:String) -> Void) {
self.myBlock = tempBlock
}
//MARK: - event
func back() {
self.dismissViewControllerAnimated(true, completion: nil)
}
func sure() {
if let string = textField?.text {
myBlock!(str: (textField?.text!)!)
self.dismissViewControllerAnimated(true, completion: nil)
}
}
}
效果圖
viewController
SecondViewController
6.數(shù)組中常用的閉包函數(shù)
6.1映射(map)
let items = [1,2,3,4,5]
let strItems = items.map { (number: Int) -> String in
return ("我是\(number)號(hào)")
}
6.2過(guò)濾器(Filter)
let score = [98,88,69,100,85,77]
let grade = score.filter { (score: Int) -> Bool in
return score >= 85
}
print(grade) //[98, 88, 100, 85]
6.3Reduce
let totle = score.reduce(0) { (totleGrade: Int, everyGrade: Int) -> Int in
return totleGrade + everyGrade
}
print(totle) //結(jié)果:517
totleGrade + everyGrade每次的運(yùn)算的結(jié)果曲線
