Swift:声明一个空字典

我开始学习swift是通过苹果公司提供的swift上的iBook-The swift Programming Language。这本书说要创建一个空字典，应该使用[:]，就像声明数组为[]一样:

我声明一个空数组，如下所示:

let emptyArr = [] // or String[]()

但是在声明空字典时，我得到语法错误:

let emptyDict = [:]

如何声明一个空字典?

当前回答

var parking = [Dictionary < String, Double >()]

^这将为[string:double]输入添加一个字典

其他回答

当你在Swift中声明任何东西时，你需要显式地告诉数据类型或类型可以推断。

斯威夫特3

下面的示例声明了一个字典，其中key为Int类型，value为String类型。

方法1:初始化器

let dic = Dictionary<Int, String>()

方法二:简写语法

let dic = [Int:String]()

方法3:字典直译

var dic = [1: "Sample"]
// dic has NOT to be a constant
dic.removeAll()

var parking = [Dictionary < String, Double >()]

^这将为[string:double]输入添加一个字典

在Swift中声明和初始化字典

字符串字典

var stringDict: [String: String] = [String: String]()

var stringDict: Dictionary<String, String> = Dictionary<String, String>()

Int字典

var stringDict: [String: Int] = [String: Int]()

var stringDict: Dictionary<String, Int> = Dictionary<String, Int>()

AnyObject字典

var stringDict: [String: AnyObject] = [String: AnyObject]()

var stringDict: Dictionary<String, AnyObject> = Dictionary<String, AnyObject>()

字符串数组字典

var stringDict: [String: [String]] = [String: [String]]()

var stringDict: Dictionary<String, Array<String>> = Dictionary<String, Array<String>>()

字符串字典数组

var stringDict: [[String: String]] = [[String: String]]()

var stringDict: Array<Dictionary<String, String>> = Array<Dictionary<String, String>>()

我通常用

var dictionary:[String:String] = [:]
dictionary.removeAll()

您可以使用以下代码:

var d1 = Dictionary<Int, Int>()
var d2 = [Int: Int]()
var d3: Dictionary<Int, Int> = [Int : Int]()
var d4: [Int : Int] = [:]

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