How is the context treated? - core-data

Question

I have a weird behaviour on Core Data with my App. I have an App where user can create their own words entries with translation. When deleting all my Core Data I checked the nb of item and it was 0. When adding later 4 items the nb of items was 5?? I found the issue after a lot of tests and it seems not consistent for me: the issue was with this code:
fileprivate func duplicateCheckAndImport() {
// Check for duplicates
do {
self.words = try context.fetch(Word.fetchRequest()) // grab all Words
let nbOfWords = words!.count
print ("The nb of words in duplicateCheck...: \(nbOfWords ?? 0)")
}
catch {
// error message to add
}
let newWord = Word(context: self.context)
do {
self.words = try context.fetch(Word.fetchRequest()) // grab all Words
let nbOfWords = words!.count
print ("The nb of words in duplicateCheck...: \(nbOfWords ?? 0)")
}
catch {
// error message to add
}
the result of the 2 prints is 0 for the first grab and 1 for the 2nd grab which means that just this line of code -> let newWord = Word(context: self.context) adds an entry in Core Data but my purpose was just to take the context add words later on like this:
let newWord = Word(context: self.context)
newWord.name = item.name.trimmingCharacters(in: .whitespaces)
newWord.definition = item.definition.trimmingCharacters(in: .whitespaces)
Can someone explain me?

Answer 1

The line of code you mention
let newWord = Word(context: self.context)
...creates a new instance. That's what Word(context: self.context) does-- it says, create a new instance of Word using the context that you pass in.
From the code you provide, it's hard to tell exactly what you're trying to do that would not create a new instance. Your variable is called newWord, which suggests that you do mean to create a new Word, and that's what's happening.
Update: If you don't want the new instance, you can delete it just like any other managed object. So if you don't want newWord, you can
context.delete(newWord)
And then save changes. There are other ways to do this, but this is the simplest.