nspredicate

Is it possible to use aggregate operator such as @min inside a predicate? BTW The predicate filters an array of objects. NSPredicate *predicate = [NSPredicate predicateWithFormat:@"ANY SELF.score == @min.score"]; I know you can retrieve the min value using the key-value operators eg: NSNumber *minScore = [myArray valueForKeyPath:@"@min.score"]; So far I only get errors about the objects not being key value compliant for "@min". Thanks The reason that you're getting that error is that the predicate is being applied to each object in myArray , and those objects apparently don't support the key

NSPredicate 谓词工具一般用于过滤数组数据,也可用来过滤CoreData查询出的数据. 1). 支持keypath 2). 支持正则表达式 在使用之前先新建3个类 Teacher Info Address,详细代码如下 Info.h #import <Foundation/Foundation.h> @interface Info : NSObject @property (nonatomic, strong) NSString *classNum; @end Info.m #import "Info.h" @implementation Info @end Address.h #import <Foundation/Foundation.h> @interface Address : NSObject @property (nonatomic, strong) NSString *detailAddress; @end Address.m #import "Address.h" @implementation Address @end Teacher.h #import <Foundation/Foundation.h> #import "Info.h" #import "Address.h" @interface Teacher : NSObject

I have three entities: EntityA, EntityB and EntityC connected with to-many relationships. See schema for details: alt text http://img706.imageshack.us/img706/9974/screenshot20091220at124.png For getting all instance of EntityA which depend from EntityB.name I use the predicate like this: NSPredicate *predicate = [NSPredicate predicateWithFormat:@"ANY EntityB.name like 'SomeName'"]; What should be predicate for getting all instance of EntityA which depend from EntityC.name? I tried query like @"ANY EntityB.entitiesC.name like 'SomeName'" but get exception "multiple to-many keys not allowed here

I am using a NSDictionary that itself contains dictionaries some keys and its values.The format is like , { "1" = { "key1" = "ss", "key2" = "rr", "name" = "nm" }, "2" = { "key1" = "tt", "key2" = "vv", "name" = "gf" }, "3" = { "key1" = "nm", "key2" = "vv", "name" = "gf" }, "4" = { "key1" = "tt", "key2" = "vv", "name" = "gf" }, } I need to filter with the case that key1 should be "tt" and key2 should "vv" using NSPredicate. Assume that mainDict = { "1" = { "key1" = "ss", "key2" = "rr", "name" = "nm" }, "2" = { "key1" = "tt", "key2" = "vv", "name" = "gf" }, "3" = { "key1" = "nm", "key2" = "vv",

I have two entities named "Category" and "Article" which have a many to many relationship. I want to form a predicate which searches for all articles where category.name is equal to some value. I have the following: NSEntityDescription *entityArticle = [NSEntityDescription entityForName:@"Article" inManagedObjectContext:managedObjectContext]; NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"title" ascending:YES]; NSArray *sortDescriptors = [[NSArray alloc] initWithObjects:sortDescriptor, nil]; NSPredicate *predicate = [NSPredicate predicateWithFormat:@"categories.name

NSPredicate：谓词，可用于数据查询、筛选。 运算符 用法 创建数组： Person * p1 = [Person new]; p1.name = @"p1"; p1.age = 1; Person * p2 = [Person new]; p2.name = @"p2"; p2.age = 2; Person * p3 = [Person new]; p3.name = @"ps3"; p3.age = 3; Person * p4 = [Person new]; p4.name = @"sp4"; p4.age = 4; NSArray * array = @[p1,p2,p3,p4]; 筛选小于3的对象 NSPredicate * predicate = [NSPredicate predicateWithFormat:@"age<3"]; NSArray * array1 = [array filteredArrayUsingPredicate:predicate]; 筛选范围内的对象 NSPredicate * predicate2 = [NSPredicate predicateWithFormat:@"age in {2,3} || name in {'p1','p2'}"]; NSArray * array2 = [array

I am making a method that will remove all of my NSManagedObjects that were not updated in the last sync. - (void)removeStaleObjects { // Delete objects that have not been updated in this sync. NSPredicate *stalePredicate = [NSPredicate predicateWithFormat:@"updated < %@", self.syncStart]; NSArray *staleObjects = [Node MR_findAllWithPredicate:stalePredicate]; for (Node *n in staleObjects) { [[NSManagedObjectContext MR_defaultContext] deleteObject:n]; } } The code keeps failing on the MR_findAll... line with [__NSDate objCType]: unrecognized selector sent to instance I have checked my syntax