Swift字典图-闭包初始化

问题描述

我有Swift字典:

private var params = [String : AnyObject]()

其中包含查询项，例如:

This contains query items like:

• "lat" ="40"
• "lon" ="100"

我想将此字典映射到 NSURLQueryItem 数组.我想使其笨拙":

I would like to map this dictionary to NSURLQueryItem array. I want to make it "swifty":

params.map{NSURLQueryItem.init}

但是我得到一个错误.即使我将地图更改为 [String:String?] .我知道我可以做一些像这样优雅的单线工作.谁能告诉我如何?

But I get an error. Even if I change the map to be [String:String?]. I know I can do something like this elegant one-liner. Can anybody tell how?

推荐答案

您为字典指定的值是否必须是可选的?在字典中，当您将其键指定为nil时，该条目将被删除.

Does your value for the dictionary need to be an optional? In a dictionary, when you assign its key as nil, the entry is deleted.

var params = [String:String?]()
params["lat"] = "40"
params["lon"] = "100"
params["key"] = "hey"
print(params) //result: ["lat": Optional("40"), "lon": Optional("100"), "key": Optional("hey")]
params["key"] = nil
print(params) //result: ["lat": Optional("40"), "lon": Optional("100")]

我建议使用非可选值字典.我已经成功编写了以下代码:

I suggest using a non optional-value dictionary. I have successfully written the code below:

import UIKit

var params = [String:String]()
params["lat"] = "40"
params["lon"] = "100"
let nsurl = params.map() {NSURLQueryItem.init(name: $0, value: $1)}
print(nsurl)
//Result:
//[<NSURLQueryItem 0x7f8252d29730> {name = lat, value = 40}, <NSURLQueryItem 0x7f8252d29700> {name = lon, value = 100}]

我希望这对您有帮助

这篇关于Swift字典图-闭包初始化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！