如何将结构加载到数组中? [英] How do you load structs into an Array?

问题描述

我正在尝试使用结构数据加载一个简单的数组.
我读过不要使用元组，而是使用结构.

以下是在操场上写的；但是数组仍然为零.

我在做什么错了?

I'm trying to load a simple array with struct data.
I've read not to use tuples so am using structs.

The following was written in playground; but the array is still nil.

What am I doing wrong?

struct person {
    var firstName:String?
    var lastName:String?
    init(firstName:String, lastName:String) {
        self.firstName = firstName
        self.lastName = lastName
    }
}

let john = person(firstName: "John", lastName: "Doe")
let rich = person(firstName: "Richard", lastName: "Brauer")
let ric = person(firstName: "Ric", lastName: "Lee")
let Merrideth = person(firstName: "Merrideth", lastName: "Lind")

var myPeople:[person]?

myPeople?.append(john)
myPeople?.append(rich)
myPeople?.append(ric)
myPeople?.append(Merrideth)

println(myPeople)

推荐答案

var myPeople:[person]?只是一个声明，因此array在此之后仍为nil.在 myPeople?.append(john)中，使用了可选链接，并且仅当 myPeople 不为零时才执行 append .试试

var myPeople:[person]? is only a declaration, so array is still nil after that. In myPeople?.append(john) optional chaining is used and append is only executed if myPeople is not nil. Try

var myPeople:[person]? = [] 
myPeople?.append(john)

或

var myPeople:[person] = [] 
myPeople.append(john)

这篇关于如何将结构加载到数组中?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！