Swift Language Reviews II

First, the data type

1, the basic type of package

Swift provides its own versions of all fundamental C and objective-c types, including for Int integers, Double and Float F or floating-point values

2. New Type

Swift introduces advanced types not found in objective-c, such as tuples.

Tuples enable you to create and pass around groupings of values.

3. Type-Safe language

Swift is a type-safe language, which means the language helps you are clear about the types of values your code can work with.

4. Data type Conversion

1. let three = 3
2. let pointOneFourOneFiveNine = 0.14159
3. let pi = Double(three) + pointOneFourOneFiveNine
4. // pi equals 3.14159, and is inferred to be of type Double

5, tuples

1. let http404Error = (404, "Not Found")

1. let (statusCode, statusMessage) = http404Error
2. print("The status code is \(statusCode)")
3. // Prints "The status code is 404"
4. print("The status message is \(statusMessage)")
5. // Prints "The status message is Not Found"

6. Optionals

1. let possibleNumber = "123"
2. let convertedNumber = Int(possibleNumber)

Type inference Convertednumber:int?

7. Optional Binding

You use the optional binding to the find out whether an optional contains a value

8, implicitly unwrapped optionals

. You write an implicitly unwrapped optional by placing an exclamation mark ( String! ) rather than a question mark ( String? ) afte R the type that is want to make optional.

Swift Language Reviews II