如何将NSMutableDictionary的setObject值分配为indexPath.section值

Question

我有NSMutableDictionary，返回结果如下：-

NSMutableDictionary *result = [NSMutableDictionary new];
distinctNames = [_aryClippedCategoryList valueForKeyPath:@"@distinctUnionOfObjects.category_id"];
for (NSString *category_id in distinctNames) {
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"category_id = %@", category_id];
NSArray *category_group = [_aryClippedCategoryList filteredArrayUsingPredicate:predicate];
[result setObject:category_group forKey:category_id];
NSLog(@"123 - %@", result); 
NSLog(@"223 - %lu", (unsigned long)distinctNames.count); 

在NSLog 123中，结果看起来像：-

17 =     (
{
"category_id" = 17;
"category_name" = "Apparel & Accessories";
"sub_category_id" = 17;
"sub_category_name" = "Fashion jewelry";
},
{
"category_id" = 17;
"category_name" = "Apparel & Accessories";
"sub_category_id" = 16;
"sub_category_name" = Wholesale;
}   
);
20 =     (
{
"category_id" = 20;
"category_name" = "Beauty & Personal Care";
"sub_category_id" = 288;
"sub_category_name" = "Pedicure & medicure";
},
{
"category_id" = 20;
"category_name" = "Beauty & Personal Care";
"sub_category_id" = 285;
"sub_category_name" = "Fragrances and perfumes";
}
);

在NSLog 223中，结果看起来像：-

223 - 2

在这种情况下，如何在CollectionView中选择category_group作为节值，并在CollectionView单元格中显示每组项目(category_id、category_name、sub_category_id和sub_categary_name(？

Answer 1

• (不推荐(您应该使用NSMutableArray而不是NSMutableDictionary。

  结构为

  Array<Dictionary<Array *> *> *
  

  代码就像这个

  NSMutableArray *groups = [NSMutableArray new];
  <# your code #>
  [groups addObject:@{
  @"category_id": category_id,
  @"infos": category_group
  }];
  

  然后

  NSString *groupID = groups[indexPath.section][@"category_id"]
  

  这是分段所需的组值。

  NSArray *infos = groups[indexPath.section][@"infos"];
  NSDictionary *info = infos[indexPath.item];
  

  这是项目的对象dict值

• (推荐(或将data转换为object。(对象NSMutableArray<Object *> *(

  然后用CCD_ 5得到区间。

  groups[indexPath.section].categoryID
  

  这是sections所需的组值。

  group = groups[indexPath.section]
  object = group.infos[indexPath.item]
  

  这是items的目标值

Answer 2

如果您像这样使用NSLog：

NSLog(@"123 - %@", result); 
NSLog(@"223 - %lu", (unsigned long)distinctNames.count); 

您明确要求它是一个字符串值，并且不会计算任何方程式。

如果你想把结果打印成Integer，你必须这样做：

NSLog(@"%@", 123 - result); 
NSLog(@"%lu", 223 - (unsigned long)distinctNames.count); 

第一个参数是字符串格式，下一个参数将用于替换此字符串中的%。所以你的计算必须在右边进行。

为了使其更加可见，最好在NSLog之前创建带有结果的局部变量。