filteredArrayUsingPredicate在swift数组中不存在

我有arrays中的“UserDetails”结构对象..我想过滤arrays中的对象。 但是在Swift数组中没有“filteredArrayUsingPredicate”选项。

我的数组创build

var arrayOfUsers:UserDetails[] = UserDetails[]() 

我的用户代码是

 struct UserDetails{ var userName:String var userID:String var userAge:String func userDescription()->String{ return "name " + userName + "age " + userID } } 

我的代码来创build对象

  for a in 1...1000{ var user:UserDetails = UserDetails(userName: "name", userID: String(a), userAge: "22") arrayOfUsers.append(user) } 

现在我想过滤arrayOfUsers哪一个有userID“1”。

Answer 1

Swift数组有一个.filter方法需要closures – 这将做到这一点：

 let filteredArray = arrayOfUsers.filter() { $0.userID == "1" } 

可以用各种方法简化闭合。 closures的完整声明看起来更像这样：

 var filteredArray = arrayOfUsers.filter( { (user: UserDetails) -> Bool in return user.userID == "1" }) 

两者的区别在于第一个是使用尾随闭包语法，速记参数名称，types推断和隐式返回。 您可以在Apple的Swift文档中阅读更多关于闭包的信息 。

Answer 2

你也可以使用NSPredicate

  var customerNameDict = ["firstName":"karthi","LastName":"alagu","MiddleName":"prabhu"]; var clientNameDict = ["firstName":"Selva","LastName":"kumar","MiddleName":"m"]; var employeeNameDict = ["firstName":"karthi","LastName":"prabhu","MiddleName":"kp"]; var attributeValue = "karthi"; var arrNames:Array = [customerNameDict,clientNameDict,employeeNameDict]; var namePredicate = NSPredicate(format: "firstName like %@",attributeValue); let filteredArray = arrNames.filter { namePredicate.evaluateWithObject($0) }; println("names = ,\(filteredArray)"); 

//结构过滤

 struct myStruct { var userid:String; var details:String; init() { userid = "default value"; details = "default"; } }; var f1 = myStruct(); f1.userid = "1"; f1.details = "Good boy"; var f2 = myStruct(); f2.userid = "2"; f2.details = "Bad boy"; var arrNames1:Array = [f1,f2]; let filteredArrayStruct = arrNames1.filter( { (user: myStruct) -> Bool in return user.userid == "1" }) println("filter array count = \(filteredArrayStruct.count)"); for filteredValues in filteredArrayStruct { println("filteredArrayStruct = ,\(filteredValues.details)"); } 

Answer 3

如果你正在过滤字典，你可以这样做。

 var visitors = [["age" : 22], ["age" : 41], ["age" : 23], ["age" : 30]] var filteredVisitors = visitors.filter({ $0["age"] < 30 }) println(filteredVisitors) //[["age" : 22], ["age" : 23]] 

那么这同样适用于你要过滤它的属性的结构

 struct Person { var age : Int? init(age: Int) { self.age = age } } var eventAttendees = [Person(age: 22), Person(age: 41), Person(age: 23), Person(age: 30)] var filteredAttendees = eventAttendees.filter({ $0.age < 30 }) 

你可以参考这篇文章的更多信息。 筛选Swift字典或对象属性的数组