On Sunday, July 26, 2009, Aaron Burghardt <[email protected]> wrote:

> Not necessarily.  If the keys are NSStrings, then they are copied when added 
> to the dictionary, but a copy of an immutable string is optimized to just 
> retain it, so the data isn't duplicated (assuming all rows have the same 
> columns in the same order, an assumption you don't seem to be making).
>

  You're probably right about the strings ... but (continued below) ...

> A reasonable idea if the circumstances require it.  It would certainly avoid 
> storing a reference to each key in each row, so it would save a little 
> memory, but with the mapping of indexes to column names, it may not be any 
> faster than a dictionary.
>

  This I've tested. It (creation and manipulation) takes less than ten
percent of the time with this method than does the dictionary
approach. A dramatic difference as I said.


> Unfortunately, I know from experience that when the row count gets above 
> 8xx,000, NSTableView can no longer accurately draw rows in the view (if they 
> are the standard-sized text fields).  But that is well beyond that magic 
> tipping point :-)
>

  It certainly does.

--
I.S.
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