Create a NSSet from NSArray based on property

Question

How does one create a NSSet of objects from an array based on a property.

e.g. Array of objects, each with a strong reference to a type pro

Answer 1

I have created a simple library, called Linq to ObjectiveC, which is a collection of methods that makes this kind of problem much easier to solve. In your case you need the Linq-to-ObjectiveC distinct method:

NSSet* dictionary = [NSSet setWithArray:[sourceArray distinct:^id(id item) {
    return [item type] ;
}]];

This returns a set where each item has a distinct type property.