predicate search on array with Core date Entity with NSDates for just a given calendar unit in date.

I'm quite sure you can't do that with Core Data and NSPredicate. You have to filter the entities after fetching them from Core Data.

yes i have already fetched the entities. now i want to filter them using predicate filtering for nsarray.

Use NSPredicate +predicateWithBlock and create date components from the date in the block and compare the components.

Sorry didnt get it? How does oredicate with block work?

NSCalendar *calendar = [NSCalendar currentCalendar];
   
NSPredicate *predicate = [NSPredicate predicateWithBlock:^BOOL(NSDate *date, NSDictionary<NSString *,id> * bindings) {
   NSDateComponents *components = [calendar components:NSCalendarUnitYear fromDate:date];
       
   if (components.year == 2015) {
      return YES;
   } else {
      return NO;
   }
}];
   
NSArray *dates = @[[NSDate date]];
NSArray *filteredDates = [dates filteredArrayUsingPredicate:predicate];

To be honest I stay away from blocks as I don't understand them fully.

over here what should be my arguments to the block if the entity i am evaulating is A and the relation object is Date.date.

so basically i want all A who have relationship Date's attribute date having year 1998 (for example)

Something like this?

@interface Entity : NSObject
@property (nonatomic) NSDate *date;
@end

@implementation Entity

@end

Entity *entity1 = [Entity new];
entity1.date = [NSDate new];
Entity *entity2 = [Entity new];
entity2.date = [NSDate dateWithTimeIntervalSince1970:902384252]; / 
NSArray *entities = @[entity1, entity2];
NSArray *filteredEntities = [self entities:entities withYear:1998];

- (NSArray *)entities:(NSArray *)entities withYear:(int)year {
    NSCalendar *calendar = [NSCalendar currentCalendar];
   
    NSPredicate *predicate = [NSPredicate predicateWithBlock:^BOOL(Entity *entity, NSDictionary<NSString *,id> * bindings) {
        NSDateComponents *components = [calendar components:NSCalendarUnitYear fromDate:entity.date];
       
        if (components.year == year) {
            return YES;
        } else {
            return NO;
        }
    }];
   
    return [entities filteredArrayUsingPredicate:predicate];
}

        NSPredicate *datePredicate = [NSPredicate predicateWithBlock:^BOOL(id evaluatedObject, NSDictionary *bindings) {
            EntityA *entityAObject = (EntityA*)evaluatedObject;
            int component = [[NSCalendar currentCalendar] component:calendarUnit fromDate:entityAObject.date.date];
            if (component == [calendarUnitValue intValue])
            {
                return YES;
            }
            else
            {
                return NO;
            }
        }];

did this. works perfectly fine! thanks a lot jsslai