sorting a nested NSMutableArray

Question

the NSMutableArray I want to sort looks like this:

 (
        {
            "title" = "Bags";
            "price" = "$200";
        },
        {
            "title" = "Watches";
            "price" = "$40";
        },
        {
            "title" = "Earrings";
            "price" = "$1000";
        }
 )

It's an NSMutableArray which contain a collection of NSMutableArrays. I want to sort it by price first then by title.

NSSortDescriptor *sortByPrices = [[NSSortDescriptor alloc] initWithKey:@"price" ascending:YES];
NSSortDescriptor *sortByTitle = [[NSSortDescriptor alloc] initWithKey:@"title" ascending:YES];

[arrayProduct sortedArrayUsingDescriptors:[NSArray arrayWithObjects:sortByPrices,sortByTitle,nil]];

However, that didn't seems to work, how to sort a nested NSMutableArray?

How didn't it work, what did you have before and after and how did you do the sort? — Wain
– Wain, Commented Jul 31, 2013 at 8:32

Anupdas · Accepted Answer · 2015-05-22 11:00:52Z

5

Try

    NSMutableArray  *arrayProducts = [@[@{@"price":@"$200",@"title":@"Bags"},@{@"price":@"$40",@"title":@"Watches"},@{@"price":@"$1000",@"title":@"Earrings"}] mutableCopy];

    NSSortDescriptor *priceDescriptor = [NSSortDescriptor sortDescriptorWithKey:@""
                                                                 ascending:YES
                                                                comparator:^NSComparisonResult(NSDictionary  *dict1, NSDictionary *dict2) {
                                                                    return [dict1[@"price"] compare:dict2[@"price"] options:NSNumericSearch];
    }];

    NSSortDescriptor *titleDescriptor = [NSSortDescriptor sortDescriptorWithKey:@"title" ascending:YES];



    [arrayProducts sortUsingDescriptors:@[priceDescriptor,titleDescriptor]];

    NSLog(@"SortedArray : %@",arrayProducts);

edited May 22, 2015 at 11:00

answered Jul 31, 2013 at 8:46

Anupdas

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2 Comments

Anupdas Over a year ago

@Desdenova Thanks, don't know how it was missed. Copied directly from xcode.

EarlySun Over a year ago

'*' is missing before 'dict1'--> comparator:^NSComparisonResult(NSDictionary dict1, NSDictionary *dict2) {

user529758 · Accepted Answer · 2013-07-31 08:33:08Z

1

I suppose the error is that price is a string. As such, it isn't compared numerically, but lexicographically. Try sorting the array using a comparator block and parsing the price inside that block instead:

[array sortUsingComparator:^(id _a, id _b) {
    NSDictionary *a = _a, *b = _b;

    // primary key is the price
    int priceA = [[a[@"price"] substringFromIndex:1] intValue];
    int priceB = [[b[@"price"] substringFromIndex:1] intValue];

    if (priceA < priceB)
        return NSOrderedAscending;
    else if (priceA > priceB)
        return NSOrderedDescending;
    else // if the prices are the same, sort by name
        return [a[@"title"] compare:b[@"title"]];
}];

answered Jul 31, 2013 at 8:33

user529758

Comments

user4003752 · Accepted Answer · 2013-07-31 08:39:10Z

0

Try this

Apple doc

This well help you

answered Jul 31, 2013 at 8:39

user4003752

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