Swift learning-Swift BASICS (5)

The previous book said: the Basic Data Types of gray and often gray

Next let's look at the advanced:

Tuples

Tuples store a key value with no type restrictions

let http404Error = (404, "Not Found")// http404Error is of type (Int, String), and equals (404, "Not Found")

There is a bunch of nonsense in the book. The tuples are written in this way. The above example is a (INT, string) type, and the type in the tuples can be defined by you.

You can also separate the variable of the tuples:

let (statusCode, statusMessage) = http404Errorprintln("The status code is \(statusCode)")// prints "The status code is 404"println("The status message is \(statusMessage)")// prints "The status message is Not Found

If you only need the part value in the tuples, you can use underscores to replace unnecessary values:

let (justTheStatusCode, _) = http404Errorprintln("The status code is \(justTheStatusCode)")// prints "The status code is 404

You can also use the index to obtain the values in the tuples:

println("The status code is \(http404Error.0)")// prints "The status code is 404"println("The status message is \(http404Error.1)")// prints "The status message is Not Found

When defining a tuples, you can name the values in the tuples so that the values can be obtained using the values:

let http200Status = (statusCode: 200, description: "OK")println("The status code is \(http200Status.statusCode)")// prints "The status code is 200"println("The status message is \(http200Status.description)")// prints "The status message is OK

By the way, a very useful part of a tuples is that they can be used as the return value of a function. As mentioned in the previous article, functions in Swift can have multiple return values.

Also, tuples are not suitable for complex data combinations. If the data is too complex, use classes or struct.