In Foundation, if I want to convert a set to an NSArray, I can use:
-[NSSet allObjects]-[NSOrderedSet array]
Why are these different?
In Foundation, if I want to convert a set to an NSArray , I
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In Foundation, if I want to convert a set to an NSArray, I can use:
-[NSSet allObjects]-[NSOrderedSet array]Why are these different?
Speculation, but:
Because when NSSet was created the only other major collection type was NSArray, which was (and still is, largely) the most common collection type. So a method called “allObjects” would obviously return an NSArray.
When NSOrderedSet was added much more recently, it had to deal with the existence of prior collections – primarily, NSArray and NSSet. So an “allObjects” method would be ambiguous. Ergo it has two methods, -array and -set.
And/or, the -array and -set methods return proxies to what are likely the same or similar classes used internally. So in a functional sense they’re a little different – those proxies will see mutations made on the original NSOrderedSet. -allObjects on the other hand does not – it genuinely creates an independent array, since its internal storage is likely a hashtable or similar that isn’t readily proxied.