arrays - 为什么我不能在 Swift 中使用数组的 append()？

Question

我得到一个:无法使用类型为“([Book])”的参数列表调用“append” 如果我使用 += 它可以找到但我不明白为什么 append() 不起作用。

struct Book
{
    var title:String
    var pageCount:Int
}

class Library
{
    var onShelfBooks:[Book] = []
    var onLoanBooks:[Book] = []
    var books:[Book]
    {
        get
        {
            return onShelfBooks + onLoanBooks
        }

        set(newBook)
        {
            onShelfBooks.append(newBook)
        }
    }
}

Answer 1

struct Book
{
    var title:String
    var pageCount:Int
}

class Library
{
    var onShelfBooks:[Book] = []
    var onLoanBooks:[Book] = []
    var books:[Book]
    {
        get
        {
            return onShelfBooks + onLoanBooks
        }

        set(newBook)
        {
            onShelfBooks.append(newBook[0])
        }
    }
}

var myLibrary = Library()

var newBook = Book(title: "Swift Development with Cocoa", pageCount: 453)

myLibrary.books = [newBook]

myLibrary.books