如何将 NSDictionary 数据添加到 NSMutableArray？
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【中文标题】如何将 NSDictionary 数据添加到 NSMutableArray？【英文标题】：how to add NSDictionary data to NSMutable Array? 【发布时间】：2015-11-30 10:25:23 【问题描述】：我正在尝试将 aDict 数据添加到 myData(NSMutable Array)，但无法添加。每当我尝试打印它（myData）。它正在打印空值。
for ( NSDictionary *aDict in responseArray)
NSLog(@"%@", aDict[@"brand"]);
myData[count]=aDict[@"brand"];
NSLog(@"%@",myData[2]);
我的数据格式为
"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"
我只想要我的 NSMutable 数组 *myData 中的“品牌”。
【问题讨论】：
for (NSDictionary *aDict in responseDictionary["data"]) ... ，我猜你有一个根对象，你只是忽略它。
【参考方案1】：
如果打印结果为空，则表示您没有创建“mydata”NSMutableArray。这是我的代码。
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);
【讨论】：
【参考方案2】：
brand 值列表
最简单的方法是：
NSArray *_brands = [responseArray[@"data"] valueForKeyPath:@"brand"];
这将为您提供一个包含所有值的数组，但一个 brand 可以在最终集合中多次出现，所以如果例如TRIUMPHbrands 在您的原始数据源中是两次，在_brands 数组中也是两次。
每个brand 只赋值一次
你可以这样做：
NSArray *_brands = [[NSSet setWithArray:[responseArray[@"data"] valueForKeyPath:@"brand"]] allObjects];
甚至那个：
NSArray *_brands = [responseArray[@"data"] valueForKeyPath:@"@distinctUnionOfObjects.brand"];
在这两种情况下，每个 brand 在您的 _brands 数组中只会出现一次，例如TRIUMPH，虽然它出现了两次，但在输出集合中只会出现一次，无论数据源有多少次具有相同的值；您可以使用您更喜欢或对您的项目更有意义的任何一个。
可变集合
如果你最后真的需要一个可变集合：
NSMutableArray *_mutableBrands = [_brands mutableCopy];
【讨论】：
【参考方案3】：试一下：如果你的字典数组包含键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"];
【讨论】：
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