Question

I have a part of my code that returns the numberOfRowsInSection.

Code

for (NSDictionary *consoleDictionary in [self arrayFromJSON]) {
    if ([[consoleDictionary objectForKey:@"model"] isEqualToString:@"PlayStation 3"]) {
        NSLog(@"%@", consoleDictionary);
    }
}

Output

2013-02-03 22:37:08.468 PageControl01[5782:c07] {
    console = PlayStation;
    game = "007 Legends";
    id = 1;
    model = "PlayStation 3";
    publisher = "Electronic Arts";
}
2013-02-03 22:37:08.478 PageControl01[5782:c07] {
    console = PlayStation;
    game = "Ace Combat: Assault Horizon";
    id = 2;
    model = "PlayStation 3";
    publisher = Namco;
}

This one is apparently right because it logs all the "PlayStation 3" model. However, this is not what I need. I want to log the number of "PlayStation 3"‘s. So I tweak the code a little bit and then this:

for (NSDictionary *consoleDictionary in [self arrayFromJSON]) {
    if ([[consoleDictionary objectForKey:@"model"] isEqualToString:@"PlayStation 3"]) {
        NSLog(@"%d", [consoleDictionary count]);
    }
}

Output

2013-02-03 22:39:43.605 PageControl01[5816:c07] 5
2013-02-03 22:39:43.605 PageControl01[5816:c07] 5

This one is pretty near yet so close. Instead of logging the number 5, it should log the number 2 since there are only 2 "PlayStation 3".

Please help.

Answer 1

You don’t need to explicitly loop through the array.

NSIndexSet *is = [array indexesOfObjectsPassingTest:^(id obj, NSUInteger idx, BOOL *stop) {
    return [[obj objectForKey:@"model"] isEqualToString:@"PlayStation 3"];
}];
int numOfPS3s = is.count;