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iOS Object-Oriented Objective-C Memory, Arrays and Loops, Oh My! Review Dictionaries and Arrays

William Forbes
William Forbes
21,469 Points
Posted by William Forbes
William Forbes
21,469 Points

NSdictionary

Hello Cna you guys take a look at my code below I cannot figure out where I F'd up!!

variable_assignment.mm 
NSArray *shoeOrder = @[@"Charles Smith", @(9.5), @"loafer", @"brown"];

NSMutableDictionary *shoeOrderDict = [[NSMutableDictionary alloc] initWithObjectsAndKeys: 
                                      @"customer", [shoeOrder objectAtIndex: 0], 
                                      @"size",     [shoeOrder objectAtIndex: 1], 
                                      @"style",    [shoeOrder objectAtIndex: 2], 
                                      @"color",    [shoeOrder objectAtIndex: 3], nil];

3 Answers

jcorum
jcorum
71,830 Points
jcorum
jcorum
71,830 Points

If you reverse the order of objects and keys yours will work:

NSMutableDictionary *shoeOrderDict = [[NSMutableDictionary alloc] initWithObjectsAndKeys: 
                                      [shoeOrder objectAtIndex: 0],@"customer", 
                                      [shoeOrder objectAtIndex: 1],@"size",
                                      [shoeOrder objectAtIndex: 2],@"style",
                                      [shoeOrder objectAtIndex: 3],@"color", nil];

As it happens, I was wrong. The challenge will accept your version, once it's corrected. I was guessing when I said they wanted the items added separately, based on how picky I've seen the editor be in other challenges!

William Forbes
William Forbes
21,469 Points
William Forbes
William Forbes
21,469 Points

Thanks again that makes alot of sense I totally forgot you have to flip them around.

jcorum
jcorum
71,830 Points
jcorum
jcorum
71,830 Points

There's always different ways to do things, but here's a version that works:

    NSArray *shoeOrder = @[@"Charles Smith", @(9.5), @"loafer", @"brown"];
    NSMutableDictionary *shoeOrderDict = [[NSMutableDictionary alloc] init];
    shoeOrderDict[@"customer"] = [shoeOrder objectAtIndex: 0];
    shoeOrderDict[@"size"] = [shoeOrder objectAtIndex: 1];
    shoeOrderDict[@"style"] = [shoeOrder objectAtIndex: 2];
    shoeOrderDict[@"color"] = [shoeOrder objectAtIndex: 3];

They wanted you to do the dictionary first, and then add to it separately.

William Forbes
William Forbes
21,469 Points
William Forbes
William Forbes
21,469 Points

Thank you for the infO! That worked! Is there a reason my code didn't work or was it because I just didnt do it the way they wanted?

Thanks