1. Get the managed context:
let managedObjectContext = (NSApplication.sharedApplication().delegate as! AppDelegate).managedObjectContext!
//Change AppDelegate for the name of the class of your Application Delegate
2. Set a variable to store the data:
var contentsOfTransactionFetchRequest = 
3. Fetch the data you need
let fetchRequest = NSFetchRequest(entityName: “Whatever”)
contentsOfTransactionFetchRequest = try! managedObjectContext.executeFetchRequest(fetchRequest)
Hope it helps, for me it’s good to have it summarized for later reference!
If you have any feedback I’m at @MarcMasVi