Is there a better way of showing multiple NSDictionaries?

Question

I have a method that contains a bunch of NSDictionaries (in fact, the only reason I have that method is to create those NSDictionaries). While I don't believe there are enough NSDictionaries initialized to visibly slow the code down as of yet, that is a good possibility in the future. I am currently just creating all the NSDictionaries separately, but is there a better way to do it while keeping its readability?

- (void)items {
 NSDictionary *item1 = @{
 @"label" : @"item1",
 @"icon" : [UIImage imageNamed:@"item1-Icon"],
 @"identifier": @"item1"};
 NSDictionary *item2 = @{
 @"label" : @"item2",
 @"icon" : [UIImage imageNamed:@"item2-Icon"],
 @"identifier": @"item2"};
 NSDictionary *item3 = @{
 @"label" : @"item3",
 @"icon" : [UIImage imageNamed:@"item3-Icon"],
 @"identifier": @"item3"};
 NSDictionary *item4 = @{
 @"label" : @"item4",
 @"icon" : [UIImage imageNamed:@"item4-Icon"],
 @"identifier": @"item4"};
 items = [ @[item1, item2, item3, item4] mutableCopy];
}

• Nate: Maybe this is sort of artificial (as perhaps you've simplified the code to show it here), but you have an ivar named items and a method named items. I would normally consider that a getter. Here, though, you're setting the items ivar, but not returning it (this method is void). If you want lazy initialization, then I'd make it -(NSMutableArray*) items;, and if the content is not dynamic, then check whether the ivar items is initialized yet, and if so, don't do it again.

Answer 1

«Two or more, use a for»
— Edsger W. Dijkstra

Okay, I am not using a for-loop, but an enumeration

NSArray *itemArray = @[
 @[@"item1",@"item1-Icon",@"item1"],
 @[@"item2",@"item2-Icon",@"item2"],
 @[@"item3",@"item3-Icon",@"item3"],
 @[@"item4",@"item4-Icon",@"item4"]
];
NSMutableArray *items = [NSMutableArray array];
[itemArray enumerateObjectsUsingBlock:^(NSArray *itemProperties, NSUInteger idx, BOOL *stop) {
 [items addObject: @{ @"label": itemProperties[0],
 @"icon": [UIImage imageNamed:itemProperties[1]],
 @"identifier": itemProperties[2]
 }];
}];

• Nate: This declaration of itemArray is still prone to cut and paste errors, especially as the list grows. Better to use a loop as in the other answer.
• vikingosegundo: in the end we dont know where the names come from. if they are as regular as in the example, they can be created as in the other answer. it they must be read for some source it wont work.
• Nate: You can only review the code you're given, and the code provided used a repeating pattern. If you're going to recommend a solution that's more brittle, requires more code to grow the array (relative to the other answer, that just involves changing the loop's end index), and is more verbose, in order to accomodate a different use case, that's not presented in the question, then you should document that in your answer. Otherwise, the answer is encouraging code cut-n-pasting.

Answer 2

To avoid code redundancy, its better to put this within a loop like the one below:

for (int i = 0; i < 4; i++) {
 NSDictionary *item = @{
 @"label" : [NSString stringWithFormat:@"item%d",i+1],
 @"icon" : [UIImage imageNamed:[NSString stringWithFormat:@"item%d-Icon",i+1]],
 @"identifier": [NSString stringWithFormat:@"item%d",i+1]};
 [items addObject:item];
}

• Nate: +1 for the loop, but in general, I'd advise against naming loop variables i when something more meaningful is available. itemIdx or index seems better to me. More important, though, is if the index is looping from 1 to 4, then loop from 1 to 4. Don't loop from 0 to 3, and then have to add 1 to the index every time you use it.
• iBhavik: Hi @Nate, I am defiantly agree with u, that loop have to be 1 to 4. But this answer saws only concept of add different NSDictionary objects to NSMutableArray. Naming convention and 1 to 4 things are besides of that, Thanks