如何在单个提取请求中调用两个NSPredicate。iOS Swift核心数据

在我的应用程序中，我使用的是核心数据。现在我想从数据库中获取数据，为此我使用fetch请求。但是我希望在单次提取请求中使用两个

nspredite

，所以我如何才能做到这一点

这是我的代码：

let feedfetch = NSFetchRequest(entityName: "Feed")
feedfetch.predicate = NSPredicate(format: "userid == %@", userid)

let fetchedPerson = try moc.executeFetchRequest(feedfetch)

但是我想使用两个或更多的谓词，那么我怎么做呢

我想在一个获取请求中调用所有这些，那么我如何才能做到这一点

let feedfetch = NSFetchRequest(entityName: "Feed")
feedfetch.predicate = NSPredicate(format: "userid == %@", userid)
feedfetch.predicate = NSPredicate(format: "is_deleted == %@", "0")
let sortDescriptor = NSSortDescriptor(key: "feed_id", ascending: false,selector: #selector(NSString.localizedStandardCompare))
feedfetch.sortDescriptors = [sortDescriptor]

let fetchedPerson = try moc.executeFetchRequest(feedfetch)

---

如果出于任何原因需要使用两个谓词（

NSPredicate

对象），而不是一行：

"(userid == %@) AND (is_deleted == %@)"

然后使用

NSCompoundPredicate

API：

feedfetch.predicate = NSCompoundPredicate(type:.AndPredicate, subpredicates:[
    NSPredicate(format: "userid == %@", userid), 
    NSPredicate(format: "is_deleted == %@", "0")])

---

如果出于任何原因需要使用两个谓词（

NSPredicate

对象），而不是一行：

"(userid == %@) AND (is_deleted == %@)"

然后使用

NSCompoundPredicate

API：

feedfetch.predicate = NSCompoundPredicate(type:.AndPredicate, subpredicates:[
    NSPredicate(format: "userid == %@", userid), 
    NSPredicate(format: "is_deleted == %@", "0")])

---

提取和排序

    let appDel: AppDelegate = UIApplication.shared.delegate as! AppDelegate
    let context:NSManagedObjectContext = appDel.managedObjectContext

    //Getting the cards with a video from Core Data filtered by  ("save")  and be an empity string  ("")  and by ("All")
    //Fetching from DB Card
    let savedCardRequestForVideo:NSFetchRequest<NSFetchRequestResult> = NSFetchRequest(entityName: "Card")

    //Creating mulit variables for filtering
    //Creating a variable "save" for filtering Core Data
    let savedCardFilterForVideo    = "save"

    //Creating a variable with an empty string "" for filtering Core Data
    let cardSortingIDForVideo      = ""

    //Creating a variable "All" for filtering Core Data
    let savedCardFilterForVideoAll = "All"

    //Creating the predicate array
     savedCardRequestForVideo.predicate = NSCompoundPredicate(type:.and, subpredicates:[
        NSPredicate(format: "saveVideoControl = %@", savedCardFilterForVideo),
        NSPredicate(format: "cardSortingID = %@", cardSortingIDForVideo),
        NSPredicate(format: "allData == %@", savedCardFilterForVideoAll)])


    //Here we are sorting the reuslts in a ascending order
    let savedSortDescriptorForVideo                = NSSortDescriptor(key: "businessName", ascending: ascendingOrDescending)
        savedCardRequestForVideo.sortDescriptors   = [savedSortDescriptorForVideo]

    //Creating a variable to hold the results that are being fetched
    let savedCardFilterResultsFoeVideo             = try! context.fetch(savedCardRequestForVideo) as! [NSManagedObject]

    //The variable savedCardsForVideo will hold the results array
    savedCardsForVideo  = savedCardFilterResultsFoeVideo  //This ia an Array<AnyObject>

让appDel:AppDelegate=UIApplication.shared.delegate为！AppDelegate
let context:NSManagedObjectContext=appDel.managedObjectContext
//从核心数据中获取视频卡，核心数据通过（“保存”）过滤，并且是empity字符串（“”）和（“全部”）
//从数据库卡取数
让savedCardRequestForVideo:NSFetchRequest=NSFetchRequest（entityName:“卡”）
//创建用于筛选的多变量
//创建用于筛选核心数据的变量“save”
让savedCardFilterForVideo=“保存”
//使用空字符串“”创建用于筛选核心数据的变量
让cardSortingIDForVideo=“”
//创建用于筛选核心数据的变量“All”
让savedCardFilterForVideoAll=“全部”
//创建谓词数组
savedCardRequestForVideo.predicate=NSCompoundPredicate（类型：。和，子预测：[
NSPredicate（格式：“saveVideoControl=%@”，savedCardFilterForVideo），
NSPredicate（格式：“cardSortingID=%@”，cardSortingIDForVideo），
NSPredicate（格式：“allData=%@”，savedCardFilterForVideoAll）]）
//在这里，我们按照升序对reuslts进行排序
让savedSortDescriptorForVideo=NSSortDescriptor（键：“businessName”，升序：升序或升序）
savedCardRequestForVideo.sortDescriptors=[savedSortDescriptorForVideo]
//创建一个变量来保存正在获取的结果
让SavedCardFilterResultsFovideo=试试！获取（savedCardRequestForVideo）为！[NSManagedObject]
//变量savedCardsForVideo将保存结果数组
savedCardsForVideo=savedcardfilterresultsfevideo//这是一个数组

提取和排序

    let appDel: AppDelegate = UIApplication.shared.delegate as! AppDelegate
    let context:NSManagedObjectContext = appDel.managedObjectContext

    //Getting the cards with a video from Core Data filtered by  ("save")  and be an empity string  ("")  and by ("All")
    //Fetching from DB Card
    let savedCardRequestForVideo:NSFetchRequest<NSFetchRequestResult> = NSFetchRequest(entityName: "Card")

    //Creating mulit variables for filtering
    //Creating a variable "save" for filtering Core Data
    let savedCardFilterForVideo    = "save"

    //Creating a variable with an empty string "" for filtering Core Data
    let cardSortingIDForVideo      = ""

    //Creating a variable "All" for filtering Core Data
    let savedCardFilterForVideoAll = "All"

    //Creating the predicate array
     savedCardRequestForVideo.predicate = NSCompoundPredicate(type:.and, subpredicates:[
        NSPredicate(format: "saveVideoControl = %@", savedCardFilterForVideo),
        NSPredicate(format: "cardSortingID = %@", cardSortingIDForVideo),
        NSPredicate(format: "allData == %@", savedCardFilterForVideoAll)])


    //Here we are sorting the reuslts in a ascending order
    let savedSortDescriptorForVideo                = NSSortDescriptor(key: "businessName", ascending: ascendingOrDescending)
        savedCardRequestForVideo.sortDescriptors   = [savedSortDescriptorForVideo]

    //Creating a variable to hold the results that are being fetched
    let savedCardFilterResultsFoeVideo             = try! context.fetch(savedCardRequestForVideo) as! [NSManagedObject]

    //The variable savedCardsForVideo will hold the results array
    savedCardsForVideo  = savedCardFilterResultsFoeVideo  //This ia an Array<AnyObject>

让appDel:AppDelegate=UIApplication.shared.delegate为！AppDelegate
let context:NSManagedObjectContext=appDel.managedObjectContext
//从核心数据中获取视频卡，核心数据通过（“保存”）过滤，并且是empity字符串（“”）和（“全部”）
//从数据库卡取数
让savedCardRequestForVideo:NSFetchRequest=NSFetchRequest（entityName:“卡”）
//创建用于筛选的多变量
//创建用于筛选核心数据的变量“save”
让savedCardFilterForVideo=“保存”
//使用空字符串“”创建用于筛选核心数据的变量
让cardSortingIDForVideo=“”
//创建用于筛选核心数据的变量“All”
让savedCardFilterForVideoAll=“全部”
//创建谓词数组
savedCardRequestForVideo.predicate=NSCompoundPredicate（类型：。和，子预测：[
NSPredicate（格式：“saveVideoControl=%@”，savedCardFilterForVideo），
NSPredicate（格式：“cardSortingID=%@”，cardSortingIDForVideo），
NSPredicate（格式：“allData=%@”，savedCardFilterForVideoAll）]）
//在这里，我们按照升序对reuslts进行排序
让savedSortDescriptorForVideo=NSSortDescriptor（键：“businessName”，升序：升序或升序）
savedCardRequestForVideo.sortDescriptors=[savedSortDescriptorForVideo]
//创建一个变量来保存正在获取的结果
让SavedCardFilterResultsFovideo=试试！获取（savedCardRequestForVideo）为！[NSManagedObject]
//变量savedCardsForVideo将保存结果数组
savedCardsForVideo=savedcardfilterresultsfevideo//这是一个数组

NSPredicate（格式：“userid==\（userid）和is'u deleted=='0'）使用和运算符类似userid==%@和is'u deleted==[NSNumber numberWithBool:FALSE]和……@LucaDavanzo工作得很好，但如何在这方面添加sortdescriptio？我认为您不能在谓词内部添加排序。您可以使用CompoundPredicateNSPredicate（格式：“userid=\（userid）和is\u deleted='0'）使用与userid类似的AND运算符==%@和is\u deleted==[NSNumber numberWithBool:FALSE]而且……@LucaDavanzo工作得很好，但我如何才能在其中添加SortDescriptor？我想你不能在谓词中添加sort。你可以使用CompoundPredicate，但我如何才能在该请求中添加NSSortDescriptor？@AndRiyth方法与在代码中相同。排序描述符附加到

NSFetchRequest

而不是

NSPredicate

。但是如何在此请求中添加NSSortDescriptor？@ANDRIY的方式与在代码中的方式相同。排序描述符附加到

NSFETCHTREQUEST

而不是

NSPredicate

。