每个
我试图将aDict数据添加到myData（NSMutable Array）中，但无法添加。每当我试图打印它（myData）时。它正在打印null。
for ( NSDictionary *aDict in responseArray){
NSLog(@"%@", aDict[@"brand"]);
myData[count]=aDict[@"brand"];
}
NSLog(@"%@",myData[2]);
我的数据采用格式
{
"data": [
{
"brand": "AMANTE",
"brand_id": 216,
"size": "XL",
"size_id": 78,
"url_path": "brands-1.html?brand=216&size=78"
},
{
"brand": "PENNY",
"brand_id": 1349,
"size": "LARGE",
"size_id": 54,
"url_path": "brands-1.html?brand=1349&size=54"
},
{
"brand": "TRIUMPH",
"brand_id": 58,
"size": "LARGE",
"size_id": 54,
"url_path": "brands-1.html?brand=58&size=54"
},
{
"brand": "BENETTON",
"brand_id": 2519,
"size": "LARGE",
"size_id": 54,
"url_path": "brands-1.html?brand=2519&size=54"
},
{
"brand": "HANES",
"brand_id": 446,
"size": "LARGE",
"size_id": 54,
"url_path": "brands-1.html?brand=446&size=54"
},
{
"brand": "JOCKEY",
"brand_id": 60,
"size": "40B",
"size_id": 76,
"url_path": "brands-1.html?brand=60&size=76"
},
{
"brand": "LOVABLE",
"brand_id": 59,
"size": "40B",
"size_id": 76,
"url_path": "brands-1.html?brand=59&size=76"
},
{
"brand": "HANES",
"brand_id": 446,
"size": "40B",
"size_id": 76,
"url_path": "brands-1.html?brand=446&size=76"
},
{
"brand": "ENAMOR",
"brand_id": 56,
"size": "40B",
"size_id": 76,
"url_path": "brands-1.html?brand=56&size=76"
},
{
"brand": "BIARA",
"brand_id": 2480,
"size": "40B",
"size_id": 76,
"url_path": "brands-1.html?brand=2480&size=76"
},
{
"brand": "PENNY",
"brand_id": 1349,
"size": "40B",
"size_id": 76,
"url_path": "brands-1.html?brand=1349&size=76"
},
{
"brand": "TRIUMPH",
"brand_id": 58,
"size": "40B",
"size_id": 76,
"url_path": "brands-1.html?brand=58&size=76"
},
{
"brand": "LIBERTINA",
"brand_id": 4167,
"size": "40B",
"size_id": 76,
"url_path": "brands-1.html?brand=4167&size=76"
},
{
"brand": "INNER SENSE",
"brand_id": 3685,
"size": "40B",
"size_id": 76,
"url_path": "brands-1.html?brand=3685&size=76"
},
{
"brand": "ANITA",
"brand_id": 3919,
"size": "40B",
"size_id": 76,
"url_path": "brands-1.html?brand=3919&size=76"
},
{
"brand": "ADIRA",
"brand_id": 2584,
"size": "40B",
"size_id": 76,
"url_path": "brands-1.html?brand=2584&size=76"
},
{
"brand": "COUCOU",
"brand_id": 2008,
"size": "40B",
"size_id": 76,
"url_path": "brands-1.html?brand=2008&size=76"
},
{
"brand": "362436",
"brand_id": 2119,
"size": "XL",
"size_id": 78,
"url_path": "brands-1.html?brand=2119&size=78"
}
],
"status": "success"
}
我只想在我的NSMutable Array*myData中使用"品牌"。
如果打印结果为null，则表示您没有创建"mydata"NSMutableArray。这是我的密码。
NSDictionary *dict = @{@"data":@[
@{
@"brand": @"AsafdsadfsdANTE",
@"brand_id": @216,
@"size": @"XL",
@"size_id": @78,
@"url_path": @"brands-1.html?brand=216&size=78"
},@{
@"brand": @"UYTIT",
@"brand_id": @216,
@"size": @"XL",
@"size_id": @78,
@"url_path": @"brands-1.html?brand=216&size=78"
},@{
@"brand": @"sFASDSADF",
@"brand_id": @216,
@"size": @"XL",
@"size_id": @78,
@"url_path": @"brands-1.html?brand=216&size=78"
},@{
@"brand": @"GERWW",
@"brand_id": @216,
@"size": @"XL",
@"size_id": @78,
@"url_path": @"brands-1.html?brand=216&size=78"
},
],
@"status":@"success"
};
NSMutableArray *myData = [NSMutableArray arrayWithObjects:@"A",@"B",@"C", nil];
NSArray *data = dict[@"data"];
for (NSDictionary *dict in data) {
NSString *brand = dict[@"brand"];
NSLog(@"%@",brand);
[myData addObject:brand];
}
NSLog(@"%@",myData);
brand值列表
最简单的方法是：
NSArray *_brands = [responseArray[@"data"] valueForKeyPath:@"brand"];
这将为您提供一个具有所有值的数组，但一个品牌在最终集合中可能是多次，因此，如果例如TRIUMPH品牌在原始数据源中是两次，那么在_brands数组中也是两次。
每个brand值仅一次
你可以这样做：
NSArray *_brands = [[NSSet setWithArray:[responseArray[@"data"] valueForKeyPath:@"brand"]] allObjects];
甚至是：
NSArray *_brands = [responseArray[@"data"] valueForKeyPath:@"@distinctUnionOfObjects.brand"];
在这两种情况下，每个品牌在您的_brands数组中只会出现一次，例如TRIUMPH，尽管它发生了两次，但在输出集合中只会发生一次，无论数据源有多少次具有相同的值；你可以使用任何你更喜欢或对你的项目更有意义的东西。
可变集合
如果您最终真的需要一个可变集合：
NSMutableArray *_mutableBrands = [_brands mutableCopy];
试着：如果你的字典数组包含关键字data，你可以直接访问：
NSMutableArray *addarra = [NSMutableArray new];
for ( NSDictionary *aDict in responseArray){
NSMutableDictionary *temp = [NSMutableDictionary new];
[temp setObject:aDict[@"brand"] forKey:@"brand"];
[addarra addobject:temp];
}
检索：
NSString *brand = [[addarra objectAtIndex:i]ObjectForKey:@"brand"];