Re: Dictionary keyed by a few sparse integers?
Re: Dictionary keyed by a few sparse integers?
- Subject: Re: Dictionary keyed by a few sparse integers?
- From: Andy Lee <email@hidden>
- Date: Fri, 29 Oct 2010 08:12:00 -0400
On Oct 29, 2010, at 7:52 AM, Graham Cox wrote:
>
> On 29/10/2010, at 10:44 PM, Roland King wrote:
>
>> It should work the way you've done it in a NSDictionary.
>>
>> Yes the numbers created by +numberWithUnsignedInteger: are distinct objects (normally, if I use low numbers they actually aren't, one of Cocoa's little optimizations I guess), however they compare as equal with isEqual: or isEqualToNumber:
>>
>> NSDictionary uses isEqual: so it should find it with no issue.
Not only that, it copies its keys. Although in this case -copy probably doesn't create a new object (since NSNumbers are immutable), in the general case you should code as if it does anyway.
>> I just threw together a 10 line program which does that, puts an entry into a dictionary keyed on an NSNumber representation of an NSUInteger and gets it out with another distinct NSNumber of the same NSUInteger, it finds it. I did also test in that case that the two NSNumbers were distinct, they were.
>
>
> Of course, you're quite right, which is why I thought it would work in the first place.
>
> Having put it back to not using the static array, it's now working fine! Gremlins....
Happens all the time. Someone should really do a study on why putting code back the way it was fixes bugs, especially after one has posted to cocoa-dev. :)
--Andy
>
> OK, need to try and work out why this didn't work first time around...
>
> --Graham
>
>
>
>
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