过滤境界与斯威夫特

Question

对象

我总是试图使用NSPredicate筛选我的境界数据库时出现以下错误。这是我已经试过：

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：

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 = "" 
} 

Answer 1

我不经常使用NSPredicate的直接，而不是我做的过滤器中内嵌谓词关闭参数中。

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) 

Answer 2

你提到的模型类的相关部分看起来像这样：

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 = "" 
} 

如果我理解正确的话，你想找到Publication实例是在其typez清单，text条目等于special。你可以表达为：

let realm = try! Realm() 
let result = realm.objects(Publication).filter("ANY typez.text = 'special'") 
print(result) 

Answer 3

我不喜欢接受的答案在这里，因为它实际上并没有回答这个问题......但后来它比我意识到帮助了我。我现在将尽可能使用闭包而不是NSPredicates。这个问题的实际答案应该是@ NSGangster的答案的一个稍微修改版本：

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.typez.filter({ $0.text == "special" } != []) }) 
    print(filterThis) 

..或者与之相近的东西。

但我所寻找的是有点不同。我需要一种方法来过滤多字字符串的确切单词，并且使用带有“CONTAINS”的NSPredicate将匹配任何包含的子字符串，例如，搜索“红色”会匹配“fred”。境界不支持“喜欢”或正则表达式还，所以使用封闭是我能得到工作的唯一的事：

//I was going for a "related terms" result for a dictionary app 
let theResults = terms.filter(
    { 
     //Looking for other terms in my collection that contained the 
     //title of the current term in their definition or more_info strings 
     $0.definition.components(separatedBy: " ").contains(term.title) || 
     $0.more_info.components(separatedBy: " ").contains(term.title) 
    } 
) 

尽可能多的一天，我花了搜索，希望这可以帮助别人带一个类似的问题。