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POFrom NSArray of NSDictionary objects, how to get an NSArray of uniques
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copied!<p>I'm writing an app that deals with Albums of pictures.</p> <p>I have the following JSON document which lists Albums.</p> <pre><code>{ "Albums": [ { "id": 1234, "Title": "My Birthday 2008", "Category": { "id": 0, "Name": "Birthdays" } }, { "id": 5678, "Title": "Disneyland Trip 2010" "Category": { "id": 1, "Name": "Trips" }, } ] } </code></pre> <p>As you can see, Albums reside in Categories.</p> <p>I've used NSJSONSerialization class to bring this into an NSDictionary object which contains an NSArray of NSDictionaries (per the "schema" of the above JSON).</p> <p>From this, I want to generate an NSArray of unique Categories NSDictionary objects. Something like:</p> <pre><code>{ "Categories": [ { "id": 0, "Name" : "Birthdays" }, { "id": 1, "Name" : "Trips" }, ] } </code></pre> <p>Scouring stackoverflow, I've found some things that seem like good building blocks</p> <pre><code>categories = [albums valueForKeyPath:@"@distinctUnionOfObjects.Category.Name"]; </code></pre> <p>but that obviously only generates an NSArray of NSStrings. What I want is it to be an NSArray of NSDictionaries which has two objects in it with keys "id" and "Name". I can't seem to put it all together to get what I want, without the poorman/brute method of nested if loops. I guess I'm looking for some utility method for the NSDictionary or NSArray classes that can help me do this faster.</p> <p>Any help is appreciated, thanks.</p>

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