问题
Does ObjectiveC provide a collection for Key-Value-Pairs, that allow a key to occur multiple times?
I try to parse a xml file into some simple structure. Every things is already working with nested NSDictionary, but now xml elements can occur multiple times.
Edit: My Solution
I choose an NSArray with KeyValuePairs, it turned out that I need something that is order sensitive, NSDictionary was not possible. Sideeffect: NSFastEnumeration is easy to implement this way for my collection.
回答1:
No, Cocoa doesn’t have such a collection. If you don’t want to use a third-party library for that you can simulate that by using a NSDictionary with NSArray values. Or you could take a look at the CHDataStructures framework.
回答2:
It wouldn't be a very good key....
Best thing is to have an NSDictionary and for each key an NSArray holding all values against that key.
回答3:
Or an NSArray holding as many NSDictionaries (or NSObjects each with a key and a value property) as you like. You will then be able to filter the array with a predicate to find all the occurrences of a particular key and their associated values.
来源：https://stackoverflow.com/questions/6278477/objectivec-key-value-pair-collection-with-duplicate-keys