countForFetchRequest in Swift 2.0

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耶瑟儿~
耶瑟儿~ 2021-02-20 10:48

I am trying to use the countForFetchRequest method on a managed object context in Swift 2.0.

I note that the error handling for executeFetchRequest

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  •  北荒
    北荒 (楼主)
    2021-02-20 11:01

    Your code is almost correct, but error needs to be a variable, in order to be passed as inout-argument with &:

    var error: NSError? = nil
    let count = managedObjectContext.countForFetchRequest(fetchRequest, error: &error)
    

    Update: As of Swift 3, countForFetchRequest throws an error:

    do {
        let count = try managedObjectContext.context.count(for:fetchRequest)
        return count
    } catch let error as NSError {
        print("Error: \(error.localizedDescription)")
        return 0
    }
    

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