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iOS Object-Oriented Objective-C Memory, Arrays and Loops, Oh My! Alloc and Init

Posted by Dáithí Ó Raghallaigh
Dáithí Ó Raghallaigh
Courses Plus Student 585 Points

Hi guys. For some reason your site isn't allowing me to pass this working code.

NSMutableDictionary *carDict = [[NSMutableDictionary alloc] initWithObjectsAndKeys: @"Make" , @"Honda", @"Model" , @"Accord", nil];

But your site says it is wrong and to check my syntax :)

Any ideas??

Thanks in advance D

variable_assignment.mm 
NSMutableDictionary *carDict = [[NSMutableDictionary alloc] initWithObjectsAndKeys: @"Make" , @"Honda", @"Model" , @"Accord", nil];

1 Answer

Stuart Wright
Stuart Wright
41,120 Points
Stuart Wright
Stuart Wright
41,120 Points

Although the way you've done it would seem more intuitive (to me, at least), you actually have the keys and values the wrong way around. The value comes before the key for each pair, according to the documentation:

NSDictionary *dict = [[NSDictionary alloc] initWithObjectsAndKeys: @"value1", @"key1", @"value2", @"key2", nil];

https://developer.apple.com/documentation/foundation/nsdictionary/1574190-initwithobjectsandkeys

Dáithí Ó Raghallaigh
Dáithí Ó Raghallaigh
Courses Plus Student 585 Points

Thanks so much!!! I knew it had to be something simple like that as my coding was fine. That little line drove me mad for hours :) Finally passed it!!

The answer was: NSMutableDictionary *carDict = [[NSMutableDictionary alloc] initWithObjectsAndKeys: @"Honda" , @"Make", @"Accord" , @"Model", nil]; NSString *myRide = [[NSString alloc] init]; myRide = [carDict valueForKey:@"Make"];