codecademy swift

Recently the landlord in Swift self-study pain and happy, this simplest weather forecast function encountered a lot of small pits, vomiting blood record code./Viewcontroller.swift//WeatherCreated by Angela on 14/11/6.//Copyright (c) 2014 Angela. All rights reserved.//ImportUIKitclassViewcontroller:uiviewcontroller {@IBOutlet var tv:uitextview? @IBAction func btnpressed (sender:anyobject) {println ("Button Clicked") Loadweather ()} override func Viewdi

//: Playground-noun:a Place where people can playImport UIKit//----Extension extension---------////function: Extend new functions (methods and properties) to existing classes, structs, enumerations//extensions in Swift do not have a name//1. Extended properties: Only calculated properties can be added and storage properties cannot be addedextension UIView {//var Issuperview = Falsevar height:cgfloat {Get { returnSelf.frame.size.

A destructor is called immediately before the instance memory of a class is freed. Use the DEINIT keyword to declare the destructor method, similar to the constructor method declared with Init. The destructor method is only applicable to class types.principle of the Destructor method　　Swift frees up resources by automatically releasing instances that are no longer needed. As described in the Chapter automatic reference count,

In Swift, a member variable (property) of a class does not need to be evaluated, but wants to execute a piece of code before (or after) assigning it a new value, which can be handled using Willset and didset. For example, the following code sample, the side length of a triangle (triangle) is always associated with a quad ( Square) is the same length as the edge.Class Triangleandsquare {var Triangle:equilateraltriangle {Willset {Square.sidelength = New

Original articles, welcome reprint. Reprint Please specify: Dongsheng's BlogSwift The program cannot be Windows other platforms compile and run, someone provides a website swiftstub.com , the left column is the Code editing window, and the right column is the Run Results window. The Swift program can be compiled and run under any platform . 650) this.width=650; "Width=" "height=" 313 "title=" day2.jpg "style=" width:500px;height:313px; "src="/HTTP/ S

Implicitly unwrapped optionals implicit parsing optionsMentioned above. Optional means that the constant or variable "has no value". The optional if declaration is used to infer whether a value exists, assuming that there is a value for the analysis value.Sometimes in the program architecture, the first time is assigned a value. The ability to determine an optional always has a value.In such a case. It is inefficient to infer and parse an optional value every time, because it is possible to dete

, value) in enumerate (shoppinglist) {println ("Item \ (index + 1): \ (value)")}Item 1:six EggsItem 2:milkItem 3:flourItem 4:baking PowderItem 5:bananasCreating and Initializing an array (creating arrays and initializing arrays)Use the initialization syntax to create an empty array of some type (without setting any initial values):var someints = int[] ()println ("someints is of type int[] with \ (someints.count) items.")Prints "someints is of type int[] with 0 items."Note that the type of the va

Working with characters (character related)In Swift, the string type represents the value of a set of ordered characters. Each character is a Unicode symbol. You can use the for-in loop to iterate through each character in a string:For character in "Dog!??" {println (character)}DOG// !// ??In Swift, you can also use the character type to explicitly create a single-character constant or variable:Let Yensign:

a line cannot be finished, the closure is very useful. For example, the array type in Swift has a map method that receives a closure expression as a parameter that is called once for each element in the array. Returns a map value that has been modified for this element (possibly other types), as specified by the closure.After a closure has been applied to each element in an array, the Map method returns a new array that contains the new mapping value

Swift -- escape closure and non-escape closure (Swift3.1), swift -- swift3.1 Escape closure and non-escape closure: There are two types of closures in Swift: Escape closure and non-escape closure. The escape closure indicates that the closure will be executed after the function is returned, while the non-escape closure indicates that the function is executed inte