如何从Core Data创build一个CSV文件（swift）

我正在构build一个核心数据（1个具有5个属性的实体）的应用程序，它们显示在一个tableView中。 现在我想导出这个数据到一个CSV文件（所以我可以发送这个文件与电话邮件），所以我可以打开它在Excel中的窗口。 我search了很多，但没有find正确的答案。 有人可以帮我或给我一个很好的解释或教程的链接？

我在快速顺便build立。

func createExportString() -> String { var merk: String? var ref: String? var beschrijving: String? var aantal: String? var wbs: String? var export = NSLocalizedString("merk, ref, beschrijving, aantal, wbs \n", comment: "") merk = Lijst.valueForKey("merk") as? String ref = Lijst.valueForKey("ref") as? String aantal = Lijst.valueForKey("aantal") as? String beschrijving = Lijst.valueForKey("beschrijving") as? String wbs = Lijst.valueForKey("wbs") as? String let merkString = "\(merk!)" ?? "-" let refString = "\(ref!)" ?? "-" let beschString = "\(beschrijving!)" ?? "-" let aantalString = "\(aantal!)" ?? "-" let wbsString = "\(wbs!)" ?? "-" export += merkString + "," + refString + "," + beschString + "," + aantalString + "," + wbsString + "\n" print("This is what the app will export: \(export)") return export } @IBAction func saveToCSV(sender: AnyObject) { exportDatabase() } func exportDatabase() { var exportString = createExportString() saveAndExport(exportString) } func saveAndExport(exportString: String) { let exportFilePath = NSTemporaryDirectory() + "export.csv" let exportFileURL = NSURL(fileURLWithPath: exportFilePath) NSFileManager.defaultManager().createFileAtPath(exportFilePath, contents: NSData(), attributes: nil) var fileHandleError: NSError? = nil var fileHandle: NSFileHandle? = nil do { fileHandle = try NSFileHandle(forWritingToURL: exportFileURL) } catch { print( "Error with fileHandle") } if fileHandle != nil { fileHandle!.seekToEndOfFile() let csvData = exportString.dataUsingEncoding(NSUTF8StringEncoding, allowLossyConversion: false) fileHandle!.writeData(csvData!) fileHandle!.closeFile() let firstActivityItem = NSURL(fileURLWithPath: exportFilePath) let activityViewController: UIActivityViewController = UIActivityViewController(activityItems: [firstActivityItem], applicationActivities: nil) self.presentViewController(activityViewController, animated: true, completion: nil) } } 

Answer 1

这是做所有你想要的一个简洁的方式 – 你传递pipe理对象的数组和一个CSV文件名的string。 该方法将您的CSV文件写入。 我相信你的代码中已经包含了大部分的东西，缺less的东西是最后两行，只是将一个string写入“Documents”目录下的一个新文件中。

 func writeCoreDataObjectToCSV(objects: [NSManagedObject], named: String) -> String { /* We assume that all objects are of the same type */ guard objects.count > 0 else { return } let firstObject = objects[0] let attribs = Array(firstObject.entity.attributesByName.keys) let csvHeaderString = (attribs.reduce("",combine: {($0 as String) + "," + $1 }) as NSString).substringFromIndex(1) + "\n" let csvArray = objects.map({object in (attribs.map({(object.valueForKey($0) ?? "NIL").description}).reduce("",combine: {$0 + "," + $1}) as NSString).substringFromIndex(1) + "\n" }) let csvString = csvArray.reduce("", combine: +) return csvHeaderString+csvString } 

现在，在代码的其他地方，你需要从这个string创buildNSData并将其添加到邮件编辑器：

 let csvString = ..... let data = csvString.dataUsingEncoding(NSUTF8StringEncoding) let composer = MFMailComposeViewController() composer.addAttachmentData(attachment: data, mimeType mimeType: "text/csv", fileName filename: "mydata.csv") 

然后，与composer php（集身体，主题等）通常的东西，并呈现给用户！

编辑：

编辑答案更好地回答这个问题。