Re: Where is NSList?
Re: Where is NSList?
- Subject: Re: Where is NSList?
- From: Jan Van Tol <email@hidden>
- Date: Tue, 27 Jul 2004 17:38:49 -0500
Would NSDictionary/NSMutableDictionary be closer to what you're looking
for?
-Jan
On Jul 27, 2004, at 5:35 PM, Tim Conkling wrote:
>
Sorry, I think I was pretty unclear in my original post.
>
>
I'm looking for a container that returns some information that
>
uniquely identifies each object added to it. This information is
>
called an iterator in the STL, but it's not used exclusively for
>
iterating over a container of objects, and I'm not actually looking to
>
iterate over a list of objects here. These iterators allow for
>
bidirectional reference between the list and the objects in the list
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-- i.e., the list knows which objects it contains; and each object, if
>
it chooses to retain the iterator returned to it by the list it is
>
added to, knows exactly where it is contained in the list.
>
>
This is very useful, because it allows for operations like deletion
>
(which take linear time in a container like an NSArray) to be done in
>
constant time (in a list container), if you have retained the iterator
>
for the object to be deleted. Importantly, these iterators remain
>
valid when the container is modified.
>
>
An array is good for quick access via index, but object lookup is
>
slow. If I have an object that I know is contained in an NSArray, and
>
I want to delete it from that array, there is no quick method of doing
>
so -- the operation is necessarily performed in linear time, AFAIK.
>
>
Again, I'm new to Cocoa, so I may be missing something, but I have
>
already looked at the documentation for NSArray and NSEnumerator, and
>
they don't seem to provide the functionality I'm looking for. But I
>
certainly apologize if I'm missing something obvious.
>
>
Thanks,
>
Tim
>
>
On Jul 27, 2004, at 5:45 PM, Shawn Erickson wrote:
>
>
>
>
> On Jul 27, 2004, at 2:39 PM, Shawn Erickson wrote:
>
>
>
>>
>
>> On Jul 27, 2004, at 2:40 PM, Tim Conkling wrote:
>
>>
>
>>> I'm surprised that Cocoa/CoreFoundation doesn't contain some sort
>
>>> of iterable (iteratable?) container. Either I'm missing something,
>
>>> or this is a rather large hole in the framework. I'm looking for a
>
>>> container that returns iterators of some sort for each object
>
>>> stored in it, so that each object knows exactly where it is in the
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>>> container (making for easy deletion, given the object to be
>
>>> deleted).
>
>>>
>
>>> How do people handle this sort of thing in Cocoa? I'm used to STL's
>
>>> map, list, et al, which use these sorts of iterators.
>
>>
>
>> Did you note NSEmuerator[1]?
>
>>
>
>> Consider review the following conceptual documentation on the
>
>> collections provided in Cocoa...
>
>>
>
>> <http://developer.apple.com/documentation/Cocoa/Conceptual/
>
>> Collections/index.html>
>
>>
>
>> -Shawn
>
>>
>
>> [1]
>
>> <http://developer.apple.com/documentation/Cocoa/Reference/
>
>> Foundation/ObjC_classic/Classes/NSEnumerator.html#//apple_ref/occ/
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>> cl/NSEnumerator>
>
>
>
> Also note NSIndexSet which is utilized by (but not exclusive to)
>
> NSArrayController for various things related to tracking object
>
> indexes in arrays, etc.
>
>
>
> <http://developer.apple.com/documentation/Cocoa/Reference/Foundation/
>
> ObjC_classic/Classes/NSIndexSet.html#//apple_ref/occ/cl/NSIndexSet>
>
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