无法使用“Any？”类型的索引为“[AnyHashable：Any]”类型的值下标

Posted 2023-03-14

【中文标题】无法使用“Any？”类型的索引为“[AnyHashable：Any]”类型的值下标

【英文标题】：Cannot subscript a value of type '[AnyHashable : Any]' with an index of type 'Any?'

【发布时间】：2019-03-08 16:09:28

【问题描述】：

我正在尝试将目标 c 函数转换为 swift 函数。

   +(NSString *)extractNameWithDictionary:(NSDictionary *)dictionary


   NSDictionary *assets = dictionary[@"assets"];
   NSDictionary *item = dictionary[@"item"];
   NSArray *facilityAssets = item[@"assets"];
   NSDictionary *facilities = facilityAssets[0];
   NSDictionary *asset = assets[facilities[@"content"]];

   return asset[scs_name] ? : @"";

到

func extractNameWithDictionary(dictionary: [AnyHashable : Any]) -> String 
    guard let assets = dictionary["assets"] as? [AnyHashable : Any],
    let item = dictionary["item"] as? [AnyHashable : Any],
    let facilityAssets = item["assets"] as? [Any],
    let facilities = facilityAssets[0] as? [AnyHashable : Any],
    let asset = assets[facilities["content"]] else  return "" 

    return asset[scs_name] ?? ""

但在最后一个常量中：let asset = assets[facilities["content"]] 我得到：

无法使用“Any？”类型的索引为“[AnyHashable : Any]”类型的值下标

有什么帮助吗？

【问题讨论】：

scs_name is not here 我想它的类型是String

【参考方案1】：

你可以试试

func extractNameWithDictionary(dictionary: [String : Any]) -> String 
    guard let assets = dictionary["assets"] as? [String : Any],
          let item = dictionary["item"] as? [String : Any],
          let facilityAssets = item["assets"] as? [Any],
          let facilities = facilityAssets[0] as? [String : Any],
          let asset = assets[facilities["content"] as? String ?? "" ] as? [String:Any] else  return "" 

  return asset[scs_name] as? String ?? ""

这个

facilities["content"]

返回您不能在名为 assets 的字典中使用的 Any，因为它的键类型为 AnyHashable

【参考方案2】：

最简单的方法是继续您的卸载系统以包含内容步骤：

    ...
    let facilities = facilityAssets[0] as? [AnyHashable : Any],
    let content = facilities["content"] as? String,
    let asset = assets[content] as? [AnyHashable: String]
    else  return "" 

您可能会从那里继续输入一些内容：

func extractNameWithDictionary(dictionary: [String : Any]) -> String 
    guard let assets = dictionary["assets"] as? [String : Any],
        let item = dictionary["item"] as? [String : Any],
        let facilityAssets = item["assets"] as? [[String : Any]],
        let content = facilityAssets.first?["content"] as? String,
        let asset = assets[content] as? [String: String],
        let name = asset[scs_name]
        else  return "" 

    return name

但是，随着您在此项目上的工作越来越多，您将希望完全摆脱 NSDictionary，并将其替换为具有类型属性的适当结构/类，而不必执行所有这些 @987654324 @疯狂。这只是因为使用了字典而不是结构或类而出现。