objective-c-literals

I have just realised that I can access NSDictionary using both objectForKey: and dict[key]? NSDictionary *coordsDict = @{@"xpos": @5.0, @"ypos": @7.2, @"zpos": @15.7}; NSLog(@"XPOS: %@", coordsDict[@"xpos"]); NSLog(@"XPOS: %@", [coordsDict objectForKey:@"xpos"]); Can anyone tell me if this has been hiding from me all along or if its some fairly recent change to the language? EDIT: The question does not generically refer to the new string literals, but more specifically to accessing NSDictionary with the same string literal syntax you would use for NSArray. I obviously overlooked this and just

This question already has an answer here: What are the details of “Objective-C Literals” mentioned in the Xcode 4.4 release notes? 3 answers Going through iTunes U Developing iOS 7 Apps for iPhone and iPad and in Lecture 3 slides, on page 120, there's a Quiz question that asks what the following line of code does. Frankly, I'm a bit stumped, and hoped someone could break it down. cardA.contents = @[cardB.contents,cardC.contents][[cardB match:@[cardC]] ? 1 : 0]; So, I get the first part, cardA.contents = a new array with cardB.contents and cardC.contents in the array. But, next comes (I guess??

Is it appreciably more efficient to create an NSMutableDictionary using a constructor [NSMutableDictionary dictionaryWithObjectsAndKeys:@"object1", @"key1", @2, @"key2", nil]; than taking the mutable copy of a literal [@{@"key1":@"object1", @"key2":@2} mutableCopy]; As Jeremy said; measure, measure, measure.... then optimize if you have a real problem. Without looking at the source, I can think of possible reasons why either might be faster and that answer may change depending on # of entries. The real question, though, is why do you have an app architecture where it matters? It is quite rare

I am reading through the iOS Developer Guide to get familiarized with the Objective-C language and currently I am having a little confusion on the topic of Container Literals and Subscript Notation as it pertains to creating objects like NSDictionary . I understand that there are several ways to create NSDictionary objects including Key-Value encoding ( dictionaryWithObjects:forKeys: and dictionaryWithObjectsAndKeys: , or their corresponding initializers). Source Link. From my understanding there are two main ways to do this and then there is another way which is by using container literals,

I read all about the new Objective-C literals, and used Xcode to convert my old code, but the indexing code didn't change. I changed it by hand but then it wouldn't compile. I saw a post that said we have to wait until iOS 6, but I want the indexing NOW! Is there any solution? David H Well, there is a way to do it! Add the indexing methods as a category to NSArray and NSDictionary, and you can get the feature for most of the classes you'd want it for. You can read up on ObjectiveC literals here . And thanks to James Webster's solution for @YES and @NO you can use them properly in your projects