[英]How to filter a NSArray by Key:value, that is in a NSDictionary
我試圖找出如何通過值“名稱”過濾掉NSArrays字典
// Is an Array of a dictionary, by key : values
var teamFilteredList = [[String:Any]]()
var teamList = [[String:Any]]()
取:
let string = "https://api/connect/"
let url = NSURL(string: string)
let request = NSMutableURLRequest(url: url! as URL)
request.httpMethod = "GET"
let session = URLSession.shared
let tache = session.dataTask(with: request as URLRequest) { (data, response, error) -> Void in
if let jsonObj = try? JSONSerialization.jsonObject(with: data!, options: .allowFragments) as! NSArray {
print(jsonObj)
teamList = jsonObj as! [[String : Any]]
DispatchQueue.main.async {
self.teamCollectionView.reloadData()
}
}
}
tache.resume()
此代碼是結果,並將其放入teamList
JSON:
({
id = 1;
logo = "testLogo";
name = "testTeam1";
"url" = "https://example.com";
},
{
id = 2;
logo = "testLogo";
name = "testTeam2";
"url" = "https://example.com";
},
{
id = 3;
logo = "testLogo";
name = "testTeam3";
"url" = "https://example.com";
})
放入teamList后的外觀示例:
let example = [[id: "1", logo: "image", name: "testTeam1", url: "https"], [id: "2", logo: "image", name: "testTeam2", url: "https"]]
嘗試過濾的代碼:
let array2Name = teamFilteredList.flatMap { $0["name"] }
teamFilteredList = teamList.reduce(teamFilteredList, { result, value in
!array2Name.contains(where: { $0 as! _OptionalNilComparisonType == value["testTeam3"] }) ? result + [value]: result
})
到目前為止,這段代碼太可怕了。 但是網上沒有別的告訴我怎么干的。 所以我被困住了。
導致崩潰:
無法轉換類型'__NSCFString'的值
更新:
我有一個收集視圖,該收集視圖是通過NSURL從獲取中填充的,該視圖為我提供了一個充滿NSArrays的Dictionary,並且我想通過該鍵將NSArray Indexes中已有的值過濾出該字典中的所有NSArray索引:名稱”
此鏈接的最終答案中已回答問題,但不是最新的,並會產生錯誤。 這里
如此,使用自定義結構和JSONDecoder
變得非常容易
創建一個結構
struct Team : Decodable {
let id : Int
let logo : String
let name : String
let url : URL
}
創建數組
var teamList = [Team]()
var teamFilteredList = [Team]()
解碼JSON
let string = "https://api/connect/"
let url = URL(string: string)!
let task = URLSession.shared.dataTask(with: url) { (data, response, error) in
if let error = error { print(error); return }
do {
self.teamList = try JSONDecoder().decode([Team].self, from: data!)
DispatchQueue.main.async {
self.teamCollectionView.reloadData()
}
} catch {
print(error)
}
}
task.resume()
並過濾數組
teamFilteredList = teamList.filter{ $0.name == "testTeam3" }
嘗試使用此謂詞
teamFilteredList.filter({ fromDict in return !array2Name.contains(where: { $0 == fromDict["name"] as? String ?? ""})})
訣竅在於,Swift的錯誤表達能力不足。 它說不don't use where
,為什么呢? 因為編譯器確實需要一個String,因為您的關閉不正確。
並且如果array2Name
也是一個字典。 嘗試將where
子句更改為:
where: { ($0["name"] as? String ?? "<<Empty1>>") == (fromDict["name"] as? String ?? "<<Empty2>>") }
因此整個功能將是:
teamFilteredList.filter({ fromDict in return !array2Name.contains(where: { ($0["name"] as? String ?? "<<Empty1>>") == (fromDict["name"] as? String ?? "<<Empty2>>") })})
如果您想學習更有效的函數式編程並且不介意使用JavaScript,請嘗試以下方法
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