swift - 如何正确打印结构？

Question

我试图在我的用户结构中存储一组存储结构，但我无法正确打印它。

struct users {
    var name: String = ""
    var stores: [store]
}

struct store {
    var name: String = ""
    var clothingSizes = [String : String]()        
}

var myFirstStore = store(name: "H&M", clothingSizes: ["Shorts" : "Small"])
var mySecondStore = store(name: "D&G", clothingSizes: ["Blouse" : "Medium"])

var me = users(name: "Me", stores: [myFirstStore, mySecondStore])
println(me.stores)

Answer 1

您正在对它们进行初始化。问题是您的 store 结构使用默认打印，这是结构名称的丑陋损坏版本。

如果你让它符合 CustomStringConvertible，它应该能很好地打印出来:

// For Swift 1.2, use Printable rather than CustomStringConvertible 
extension Store: CustomStringConvertible {
    var description: String {
        // create and return a String that is how
        // you’d like a Store to look when printed
        return name
    }
}

let me = Users(name: "Me", stores: [myFirstStore, mySecondStore])
println(me.stores)  // prints "[H&M, D&G]"

如果打印代码相当复杂，有时实现Streamable会更好:

extension Store: Streamable {
    func writeTo<Target : OutputStreamType>(inout target: Target) {
        print(name, &target)
    }
}

附注约定是让结构等类型以大写字母开头