Learn from the zero-starting Swift learning Note (Day58) specification for variable or constant declarations of--swift coding specifications

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A declaration is a specification that needs to be followed when declaring variables, constants, properties, methods, or functions, and custom types.

The first time a variable or constant is declared in each row, the number of variables or constants is recommended on one line, as this facilitates writing comments. The sample code is as follows.

Recommended Use:

Let level = 0var size = 10

It is not recommended to use:

let level = 0; var size =10

data for variables or constants type, and if possible, type inference should be used so that the code is concise. The sample code is as follows.

Recommended Use:

Let level = 0var size = 10

It is not recommended to use:

Let Level:int = 0var Size:int = 10

If it is not the default data type, you need to explicitly declare the data type of the variable or constant. The sample code is as follows.

Let level:int8 = 0var Size:int64 = 10

you need to use a colon when specifying a data type ( : ), size There is no space between the colon, and there is a space between the colon and the data type. The sample code is as follows.

Recommended Use:

Let level:int8 = 0var Size:int64 = 10

It is not recommended to use:

Let level:int8 = 0var Size:int64 = 10

Use as much as possible when working with data types Swift The data type itself, for example:

Recommended Use:

Let width = 120.0 let widthstring = "Hello." var devicemodels: [String]var employees: [Int:string]

It is not recommended to use:

Let Width:nsnumber =120.0 let widthstring:nsstring = "Hello." var Devicemodels:nsarrayvar employees:nsdictionary

Property declaration

properties include storage properties and computed properties, if the declaration specification for a stored property is the same as the specification of a variable or constant declaration. If the computed property is similar to a code block, when you use a read-only computed property, you may want to omit the get statement. The sample code is as follows.

Recommended Use:

var fullname:string {return firstName + "." + LastName}

It is not recommended to use:

var fullname:string {get {return firstName + "." +lastname}}

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Learn from the zero-starting Swift learning Note (Day58) specification for variable or constant declarations of--swift coding specifications