iphone - 返回 objectForKey 的数量

Question

我有一部分代码返回 numberOfRowsInSection。

代码

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

输出

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;
}

这显然是正确的，因为它记录了所有 "PlayStation 3" 模型。但是，这不是我需要的。我想记录 "PlayStation 3" 的数量。所以我稍微调整了代码，然后是:

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

输出

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

这个很近，但又很近。它不应记录数字 5，而应记录数字 2，因为只有 2 "PlayStation 3" .

请帮忙。

Answer 1

您不需要明确地遍历数组。

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