Download as PDF, PPTX
Uploaded byFutada Takashi
SWIFT1 Optional
The document discusses Swift and compares it to other languages like Java and Scala. It provides code examples of basic Swift concepts like variables, optionals, and error handling. The key points are: - Swift is being studied with Xcode playgrounds rather than Eclipse like Java or Idea like Scala. - Examples show the basics of Swift syntax including variables, printing, and type inference. - Optionals are covered, which allow values to contain nil using a ?. Methods for safely accessing optionals with if let or nil coalescing are demonstrated. - Exceptions in other languages like Java are criticized for being difficult to trace, and Swift error handling is presented as a cleaner alternative.
More Related Content
SWIFT1 Optional
- 1.
- 2. Java < Scala< Swift Java + Eclipse = COBOL Scala + Idea = cool but tricky Swift + Xcode = easy and fun
- 3. Let’s study Swift. Swift Wer gonna study Swift with Playground.
- 4. Hello World var str:String = “SWIFT” println(“Hello (str) World”)
- 5. Type Inference var list:String = “Hello World” var list = “Hello World” var obj: MyClass = MyClass() var obj = MyClass() noun: Inference verb: Infer reference report
- 6. ? var value: Optional<Int> varvalue: Int? ? indicates that the value may contain nil. func getValueThisMayReturnNil() -> String? func getValueThisWillNotReturnNil() -> String var ret = getValueThisWillNotReturnNil() if ret != nil { // this does not make sense! ret.doSometing()
- 7. func getValueThisMayReturnNil() ->String? if let ret = getValueThisMayReturnNil() // Unwrappe if Some { ret.doSometing() // normal } else { // Nil } https://www.youtube.com/watch?v=KSkPE_-gBkc&index=4&list=PLy7oRd3ashWodnpf8rjfYEkTgwbOEsKfU&spfreload=1
- 8. ! var value: String? Howto get a content of the Optional value? var ret = value! // get var ret = value ?? “It is nil” // getOrElse
- 9. Exceptions Suck We arereally sick and tired of Java Exceptions. Exceptions remind me of GO TO statement. try { int val = String(“xxx”).parseInt(); doSomething…; doSomething…; doSomething…; doSomething…; doSomething…; doSomething…; } catch(Exception e) { // What has happened ??? // i don’t care…. just throws e; }