Question

我想通过我的自定义对象 BETWEEN 进行号码比较。 我已完成字符串比较，但数字比较喊出错误，如下面的代码所示。

class CustomClass: NSObject {
    var name        : String?
    var aWidth      : CGFloat!
}

有效的字符串比较

let predicate = NSPredicate(format: "SELF.name contains[c] %@","Sal")

无论其

let predicate = NSPredicate(format: "SELF.aWidth > 0 AND SELF.aWidth < 50")

let predicate = NSPredicate(format: "SELF.aWidth < 50")

我知道这个错误。

let predicate = NSPredicate(format: "SELF.aWidth BETWEEN {%@, %@}", {minWidth, maxWidth})

原因：＆＃39; [＆lt; test.CustomClass 0x7fe86274bfd0＆gt; valueForUndefinedKey：]：此类与键 aWidth 不符合键值编码。＆＃39;

所有对此错误的搜索都会带给我故事板问题。

如何使用BETWEEN编写谓词？提前致谢

更新

我还发现了这个关于在swift 中使用过滤器的例子，这很有帮助。但我仍然有问题。

class Person : NSObject { var age : CGFloat? init(age: CGFloat) { self.age = age } }

过滤

let eventAttendees = [Person(age: 22), Person(age: 41), Person(age: 23), Person(age: 30)] let filteredAttendees = eventAttendees.filter({ $0.age < 30 }) for person in filteredAttendees { print(person.age!) }

当我尝试使用相同的技术时，我这次出现错误。

第一种方法

let array = self.testDictionary.allValues as Array var filteredArray = array.filter( { (user: Person) -> Bool in return $0.age < 30 })


匿名闭包参数不能在具有的闭包内使用   显式参数

第二种方法

let array = self.testDictionary.allValues as Array var filteredArray = array.filter( { (user: Person) -> Bool in return true })


无法转换类型＆＃39;（人物）＆＃39;的值 - ＆GT;布尔对预期的争论   输入＆＃39;（Anyobject）＆＃39; - ＆GT;布尔

由于

Answer 1

首先更新Xcode以使用Swift 2。

假设您有字典ctest

[Int:CustomClass]

获取值数组（编译器知道它包含let testDictionary = [1: CustomClass(name: "Foo", aWidth: 1.0), 2: CustomClass(name: "Bar", aWidth: 25.0), 3: CustomClass(name: "Baz", aWidth: 75.0)]个实例）

CustomClass

然后您可以使用let array = Array(testDictionary.values)函数

filter

Answer 2

通过添加构造函数来初始化

来修改您的类

class CustomClass: NSObject {
    var name        : String?
    var width      : CGFloat = 0.0

    // *** define constructor ***
    init(name: String, width: CGFloat) {
        self.name = name
        self.width = width
    }
}

// *** Declare Array ***
let arrObjects = NSMutableArray()

// *** create objects and add to array ***
let obj1 = CustomClass(name: "Scale", width: 200.0)
self.arrObjects.addObject(obj1)

let obj2 = CustomClass(name: "Pen", width: 40.0)
self.arrObjects.addObject(obj2)

print("1. Filter on String")   
// *** 1. Filter on String ***
var predicate = NSPredicate(format: "SELF.name contains[c] %@","sca")
var filteredArray = self.arrObjects.filteredArrayUsingPredicate(predicate)

for object in filteredArray
{
    let obj = object as! CustomClass
    print("\(obj.name!) \(obj.width)")
}

print("2. Filter on CGFloat")

// *** 2. Filter on CGFloat ***
predicate = NSPredicate(format: "width > %f AND width < %f",0.0, 50.0)

filteredArray = self.arrObjects.filteredArrayUsingPredicate(predicate)

for object in filteredArray
{
    let obj = object as! CustomClass
    print("\(obj.name!) \(obj.width)")
}


print("3. Filter using BETWEEN")
// *** 3. Filter using BETWEEN ***
predicate = NSPredicate(format: "width BETWEEN {%f, %f}",0.0, 50.0)
filteredArray = self.arrObjects.filteredArrayUsingPredicate(predicate)

for object in filteredArray
{
    let obj = object as! CustomClass
    print("\(obj.name!) \(obj.width)")
}

引自NSHipster blog by Mattt Thompson

Answer 3

对于swift 4 +：

，要在数组使用中对自定义对象使用谓词，如下所示

func checkIfJobIdContains(array:NSArray, job_id: String) -> Bool
{
    let temp = array.filter({ (result) -> Bool in
    let modelObj = result as! ModalMultipleJobRequestsPage
    if modelObj.job_id == job_id
    {
        return true
    }
    else
    {
        return false
    }
    })

    if temp.count != 0
    {
        return true
    }
    return false
}

如何编写NSPredicate自定义对象（CGFloat var）BETWEEN操作

3 个答案: