使用Swift过滤Realm对象 [英] Filtering Realm objects with Swift

问题描述

尝试使用NSPredicate过滤Realm数据库时，总是出现以下错误:

I always get the following error when trying to filter my Realm database using NSPredicate:

属性文本"不是类型为"getType"的对象中的链接

Property 'text' is not a link in object of type 'getType'

我想过滤我的Realm数据库以仅显示其中包含某些特定文本的项目.这是我尝试过的:

I want to filter my Realm database to show only the items that have some specific text in them. This is what I've tried:

let realm = try! Realm()
let predicate = NSPredicate(format: "typez.text.filter = 'special'")
let filterThis = realm.objects(Publication).filter(predicate)
print(filterThis)

我的模型类的相关部分是:

The relevant portion of my model classes is:

class Publication: Object, Mappable {
    dynamic var id: Int = 0
    var typez = List<getType>()
    dynamic var url: String?
}

class getType: Object, Mappable {
    dynamic var text: String = ""
}

推荐答案

我通常不直接使用NSPredicate's，而是在过滤器参数内执行内联谓词关闭.

I don't usually use NSPredicate's directly, instead I do an inline predicate closure within the filter paramter.

let realm = try! Realm()
                     //Array of publications             
    let realmObjects = realm.objects(Publication)
    //any publication where .text property == special will be filtered. and filter out empty array
    let filterThis = realmObjects.filter({ $0.getType.filter({ $0.text == "special" } != [] ) })
    print(filterThis)

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