Swift核心数据-具有不同结果的请求 [英] Swift Core Data - Request with distinct results

问题描述

如何快速调用具有不同值的es请求?

how I can call es request with distinct values in swift?

这是我的代码:

let appDelegate: AppDelegate = UIApplication.sharedApplication().delegate as AppDelegate
    let context: NSManagedObjectContext = appDelegate.managedObjectContext

    let request = NSFetchRequest(entityName: "MedicalData")
    request.propertiesToFetch = NSArray(object: "docID")
    request.returnsObjectsAsFaults = false
    request.returnsDistinctResults = true

    var results:NSArray = context.executeFetchRequest(request, error: nil)

    for data in results {
        var thisData = data as MedicalData
        println(thisData.docID)
    }

我想获取"docID"的不同值，但是我得到了所有的实体:(

I want to get distinct values for "docID" but I get all of the entity :(

感谢您的帮助！

推荐答案

您需要设置

request.resultType = NSFetchRequestResultType.DictionaryResultType

它返回字典，但是不同的过滤器应该起作用.

It returns dictionaries, but the distinct filter should work.

如果您不想沿着那条路线走，请在内存中过滤(也建议).进行正常提取，然后

If you do not want to go down that route, filter in memory (also recommended). Do a normal fetch and then

let distinct = NSSet(array: results.valueForKeyPath("docID") as [String])

我更喜欢Swift 2.0

With Swift 2.0 I prefer

let distinct = NSSet(array: results.map { $0.docID })

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