This is a Category on NSManagedObject, that enables subscript access to properties.

README

This is a Category on NSManagedObject, that enables subscript access to properties. 

I find this useful as I prefer (for several reasons) not to compile against my model entities but to access them as I would a NSDictionary, with string constants for keys.

So instead of 
  [myEntity valueForKey:@"title"]

you can use 
  myEntity[@"title"]

and instead of 
  [myEntity setValue:@"Hello World" forKey:@"title"]

you can use 
  myEntity[@"title"] = @"Hello World"

Enjoy!

NSManagedObject+KeyedSubscript.h

//
//  NSManagedObject+KeyedSubscript.h
//
//  Created by Jeremy Quinn on 25/05/2013.
//  Copyright (c) 2013 FiveOne.org. All rights reserved.
//
 
#import <CoreData/CoreData.h>
 
@interface NSManagedObject (KeyedSubscript)
 
// getter
- (id)objectForKeyedSubscript:(NSString*)key;
 
// setter
- (void)setObject:(id)object forKeyedSubscript:(id<NSCopying>)key;
 
@end

NSManagedObject+KeyedSubscript.m

//
//  NSManagedObject+KeyedSubscript.m
//
//  Created by Jeremy Quinn on 25/05/2013.
//  Copyright (c) 2013 FiveOne.org. All rights reserved.
//
 
#import "NSManagedObject+KeyedSubscript.h"
 
@implementation NSManagedObject (KeyedSubscript)
 
- (id)objectForKeyedSubscript:(NSString*)key {
    return [self valueForKey:key];
}
 
- (void)setObject:(id)object forKeyedSubscript:(id<NSCopying>)key {
    NSParameterAssert([(id<NSObject>)key isKindOfClass:[NSString class]]);
    [self setValue:object forKey:(NSString*)key];
}
 
@end