swift阵列中不存在filteredArrayUsingPredicate
swift阵列中不存在filteredArrayUsingPredicate
提问于 2014-06-24 17:08:05
我在数组中有"UserDetails“结构对象..我想从数组中过滤对象。但是在Swift数组中没有"filteredArrayUsingPredicate“的选项。
我的数组创建
var arrayOfUsers:UserDetails[] = UserDetails[]()我的用户详细信息代码是
struct UserDetails{
var userName:String
var userID:String
var userAge:String
func userDescription()->String{
return "name " + userName + "age " + userID
}
}我创建对象的代码
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userID为"1“的arrayOfUsers。
回答 4
Stack Overflow用户
回答已采纳
发布于 2014-06-24 17:16:05
Swift数组有一个接受闭包的.filter方法--如下所示：
let filteredArray = arrayOfUsers.filter() { $0.userID == "1" }可以通过多种方式简化闭包。闭包的完整声明看起来更像这样：
var filteredArray = arrayOfUsers.filter( { (user: UserDetails) -> Bool in
return user.userID == "1"
})两者之间的区别在于，第一种是使用尾随闭包语法、速记参数名称、类型推断和隐式返回。你可以阅读more about closures in Apple's Swift documentation。
Stack Overflow用户
发布于 2014-06-24 21:05:21
您也可以使用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)");
}Stack Overflow用户
发布于 2014-12-18 05:59:10
如果你正在过滤一个字典，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]]同样的道理也适用于你要过滤其属性的结构
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了解更多信息。Filtering a Swift Array of Dictionaries or Object property
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/24382580
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