Help for NSPredicate, please…

[fiz]

Hello,

What’s wrong in this syntax?

NSPredicate *predicate = [NSPredicate predicateWithFormat: @“(NOT self IN self.avoidances) AND (NOT SELF == $SELF)”];

The goal is to get an array of objects which are different from the caller and not included in a set of caller’s entities. For example, a menu giving choices for a relationship with an object A has to list every object EXCEPT the object A itself and objects that are already in relation with A.

I get “Unable to parse the format string” error and I can’t understand how to formulate this.

Thanks,

[StefanK]

Hi,

try a block predicate

  NSPredicate *predicate = [NSPredicate predicateWithBlock: ^BOOL(id obj, NSDictionary *bind){
		return ![self.avoidances containsObject:obj] && obj != self;
	}];

[fiz]

Thank You Stefan. I had to modify your code slightly to insert it in the Document method, because “self” refers to the document:

NSManagedObject *selectedPeople = [self.students.selectedObjects lastObject];
NSManagedObjectContext *moc = [self managedObjectContext];
NSEntityDescription *entityDescription = [NSEntityDescription entityForName:@“Student” inManagedObjectContext:moc];
NSFetchRequest *request = [[NSFetchRequest alloc] init];
[request setEntity:entityDescription];
NSPredicate *predicate = [NSPredicate predicateWithBlock: ^BOOL(id obj, NSDictionary *bind){
return ![[selectedPeople valueForKey:@“avoidances”] containsObject:obj] && obj != selectedPeople;
}];
[request setPredicate:predicate];
NSArray *array = [moc executeFetchRequest:request error:nil];
[self.notAvoidances setContent:array];

The Predicate with format could use “SELF” because it is a fetch property of the entity “Student”. By the way, fetch properties declared this way seem to wait for the PersistantStoreCoordinator to save the context before returning a correct array.

Well, the same question on StackOverflow is still waiting for an answer for more than a week now…

Thank you ! Sometimes I wonder if you are dreaming in Objective-C…

[StefanK]

@fiz

Sometimes I wonder if you are dreaming in Objective-C…

Definitely no