extracting properties from NSArray of objects

问题

Is there any of way (other than looping) of extracting a particular property of all objects in an array. So say there in an array of people. I want to extract all their first names into an array.

回答1:

Key Value coding will help you with that:

NSArray *result = [people valueForKey:@"firstname"];

回答2:

I got answer for my question. This is how we can achieve the same in swift.

let arraytWithProperties = arrayWithObjects.map{ $0.propertyName }

来源：https://stackoverflow.com/questions/12312032/extracting-properties-from-nsarray-of-objects