Re: Cocoa-dev Digest, Vol 7, Issue 496
Re: Cocoa-dev Digest, Vol 7, Issue 496
- Subject: Re: Cocoa-dev Digest, Vol 7, Issue 496
- From: Rick Mann <email@hidden>
- Date: Mon, 3 May 2010 11:57:39 -0700
On May 3, 2010, at 11:55:33, Dan Rowley wrote:
> Yes, that's what I meant. "self in %@". This would evaluate to true in any
> case where the object exists in the specified set. At least theoretically,
> as I'm not sure I understood your original question completely. :)
>
> I haven't actually tried this, but theoretically simple membership lookups
> on a set would be much quicker than the same on an array, so you might
> consider a set of missions instead of an array for this operation.
Well, I have an array as a result of a previous query, so that'll have to do. It's small, though, so I'm not too worried. Thanks!
>
>
> D
>
>
>
>
> On 5/3/10 11:17 AM, "email@hidden"
> <email@hidden> wrote:
>
>>
>> Wrong assumption; you would actually use "SELF" in a format string, as it is a
>> reserved word. So @"SELF IN %@"
>>
>> I think...
>>
>>
>> Fred Reimer, CCIE 23812 CISSP 107125
>> mailto:email@hidden
>>
>>
>>
>> On May 2, 2010, at 4:32 PM, Frederick Reimer wrote:
>>
>>> Unfortunately, there is nothing for the NSPredicate class to go on to assume
>>> what object you are talking about. predicateWithFormat is a class
>>> method/selector/function. What object is it supposed to assume you mean if
>>> one is not supplied?
>>>
>>> Dan Rowley sent me an email saying you may be able to use "self." So, I
>>> assume this means:
>>>
>>> NSPredicate *pred = [NSPredicate predicateWithFormat: @"%K in %@", self,
>>> favoriteMissions];
>>>
>>> HTH,
>>>
>>> On May 2, 2010, at 9:03 AM, Rick Mann wrote:
>>>
>>>> I saw that, I had hoped that by not specifying an attribute, it would mean
>>>> the object itself, not an attribute on the object.
>>>>
>>>>
>>>> On May 2, 2010, at 05:58:39, Frederick Reimer wrote:
>>>>
>>>>> The manuals for this give the following example:
>>>>>
>>>>> NSPredicate *inPredicate =
>>>>> [NSPredicate predicateWithFormat: @"attribute IN %@",
>>>>> aCollection];
>>>>>
>>>>> It looks like you are missing the attribute... If attribute can vary, you
>>>>> can use a %K and a NSString value representing the attribute name (it is
>>>>> not automatically enclosed in quotes as %@ values are).
>>>>>
>>>>> HTH,
>>>>>
>>>>> Fred
>>>>> On May 2, 2010, at 8:27 AM, Rick Mann wrote:
>>>>>
>>>>>> Hi.
>>>>>>
>>>>>> I have two entities: Mission and Favorite. Favorite has a single relation
>>>>>> to Mission. I need to fetch all Mission objects that exist in Favorite.
>>>>>> I'm using an NSFetchResultsController.
>>>>>>
>>>>>> I created an array with all the Mission objects found in the Favorite
>>>>>> entity. Then I tried to create a predicate like this:
>>>>>>
>>>>>> NSPredicate* pred = [NSPredicate predicateWithFormat: @"in %@",
>>>>>> favoriteMissions];
>>>>>>
>>>>>> and use that on a fetch of Mission objects. But it complains that it can't
>>>>>> parse that format string.
>>>>>>
>>>>>> Clearly, this approach isn't going to work. I could store the Mission's
>>>>>> key in the Favorite table instead, but that's less elegant. Might be the
>>>>>> only way to go.
>>>>>>
>>>>>> Any suggestions?
>>>>>>
>>>>>> tia,
>>>>>> Rick
>
>
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