Question

我在Code Data中存储了一个名为Users的表。我只是试图从返回的数据数组中提取“FirstName”，但在我的控制台中继续“nil”。

let fetchRequest = NSFetchRequest(entityName:"Users")

let fetchedResults =

managedContext.executeFetchRequest（fetchRequest，错误：＆amp;错误）为？ [用户]

    var arrayvalues=NSArray(array: fetchedResults!)

    if let results = managedObject?.executeFetchRequest(fetchedResults, error: nil) as? [Users] {
        let someObject = results[firstName]
    }

我的用户类如下：

class Users: NSManagedObject {

@NSManaged var email: String
@NSManaged var firstName: String
@NSManaged var fLast: String
@NSManaged var fullName: String
@NSManaged var id: String
@NSManaged var isActive: String
@NSManaged var lastName: String
@NSManaged var lastupdated: String
@NSManaged var role: String
@NSManaged var uPass: String

}

我一直在寻找实现这一目标的方法，但似乎无法获取任何FirstNames ......

Answer 1

替换

if let results = managedObject?.executeFetchRequest(fetchedResults, error: nil) as? [Users] {
    let someObject = results[firstName]
}

通过

var firstNames = [String]() // empty array to keep the firstNames
if let results = managedObject?.executeFetchRequest(fetchedResults, error: nil) as? [Users] {
    for user in results  {
        firstNames.append(user.firstName)
    }
}

我的代码段在firstNames数组中添加了每个用户的firstName。您必须意识到代码中的 someObject 不是单个用户而是用户数组。

从Swift中的CoreData获取数据数组

1 个答案: