Question

I am trying to get the index from the for loop while looping inside [NSManagedObject] I tried below code. anyone has idea how to get it.

Error : Type '[NSManagedObject]?' does not conform to protocol 'SequenceType'

    for (index, item) in RestaurantQuestions.all() {

        print(index) // should print index
       //Doing my stuff

    }

is there any way to do it?

Answer 1

可能是因为可选类型。试着摆脱这样的选择：

if let questions = RestaurantQuestions.all() {
    for (index, item) in questions.enumerate() {
        print(index) // should print index
        //Doing my stuff
    }
}

Answer 2

您可以使用.enumerate()在Swift 2.0及更高版本中执行此操作，如下所示：

for (index, item) in RestaurantQuestions.all()!.enumerate() {
    print(index) // should print index
    //Do your stuff
}

它返回一个带索引的元组和数组中每个项的值。但是，在这种情况下，RestaurantQuestions.all()必须返回有效数组。

Get Index from for loop looping inside NSManagedObject

2 个答案: