swift - 将 if 子句转换为可选值

Question

我正在尝试将大量 if 子句转换为 Swift 中的可选值。我仍然收到 let name 语句的错误。我收到的错误是:

Type 'int' does not conform to protocol 'StringLiteralConvertible'.

我有两个问题:

1. 我的新代码与旧代码有相同的用途吗？
2. 如何消除此错误？

谢谢。

Old Code:

class func jsonAsUSDAIdAndNameSearchResults (json: NSDictionary) -> [(name: String, idValue: String)] {

    var usdaItemsSearchResults: [(name: String, idValue: String)] = []
    var searchResult: (name: String, idValue: String)

    if json["hits"] != nil {
        let results: [AnyObject] = json["hits"] as [AnyObject]
        for itemDictionary in results {
            if itemDictionary["_id"] != nil {
                let idValue:String = itemDictionary["_id"] as String
                if itemDictionary["fields"] != nil {
                    let fieldsDictionary: NSDictionary = itemDictionary["fields"] as NSDictionary
                    if fieldsDictionary["item_name"] != nil {
                        let name: String = fieldsDictionary["item_name"] as String
                        searchResult = (name: name, idValue: idValue)
                        usdaItemsSearchResults += [searchResult]
                    }
                }
            }
        }
    }
    return usdaItemsSearchResults
}

New code:

class func jsonAsUSDAIdAndNameSearchResults (json: NSDictionary) -> [(name: String, idValue: String)] {

    var usdaItemsSearchResults: [(name: String, idValue: String)] = []
    var searchResult: (name: String, idValue: String)

    if json["hits"] != nil {
        let results: [AnyObject] = json["hits"] as [AnyObject]
        for itemDictionary in results {
            let name: String? = itemDictionary["_id"]?["_fields"]?["item_name"]? as? String
            let idValue:String? = itemDictionary["_id"]? as? String
            if (name? != nil && idValue? != nil) {
                searchResult = (name: name!, idValue: idValue!)
                usdaItemsSearchResults += [searchResult]
            }
        }
    }
    return usdaItemsSearchResults
}

感谢大家的大力支持，我们才得以实现这一目标。在这个新版本中，我收到错误“使用未解析的标识符‘名称’”。此错误发生在流量控制 if (name?!= nil ...) 级别。

这是新代码:

        class func jsonAsUSDAIdAndNameSearchResults (json: NSDictionary) -> [(name: String, idValue: String)] {

    var usdaItemsSearchResults: [(name: String, idValue: String)] = []
    var searchResult: (name: String, idValue: String)

    if json["hits"] != nil {
        let results:[AnyObject] = json["hits"]! as [AnyObject]
        for itemDictionary in results {
            if let name = ((itemDictionary["_id"] as! NSDictionary)["_fields"] as! NSDictionary)["item_name"] as? String {break}
            if let idValue = itemDictionary["_id"] as? String {break}
            if (name? != nil && idValue? != nil) {
                searchResult = (name: name!, idValue: idValue!)
                usdaItemsSearchResults += [searchResult]
            }
        }
    }
    return usdaItemsSearchResults
}

Grimxn 值得一枚奖牌!我们就快到了。以下代码不再显示任何问题，但我们在运行它时遇到了断点。选角好像有问题。

class func jsonAsUSDAIdAndNameSearchResults (json: NSDictionary) -> [(name: String, idValue: String)] {

        var usdaItemsSearchResults: [(name: String, idValue: String)] = []
        var searchResult: (name: String, idValue: String)

        if json["hits"] != nil {
            let results:[AnyObject] = json["hits"]! as [AnyObject]
            for itemDictionary in results {
                let fields: NSDictionary = (itemDictionary["_id"]? as NSDictionary)["_fields"]? as NSDictionary
                let name:String? = fields["item_name"] as? String
                let idValue:String? = itemDictionary["_id"]? as? String
                if (name? != nil && idValue? != nil) {
                    searchResult = (name: name!, idValue: idValue!)
                    usdaItemsSearchResults += [searchResult]
                }
            }
        }
        return usdaItemsSearchResults
    }

已经解决了。该代码的工作原理如下。我进行了错误的深入研究。真的谢谢你，我学到了很多东西:

         class func jsonAsUSDAIdAndNameSearchResults (json: NSDictionary) -> [(name: String, idValue: String)] {

    var usdaItemsSearchResults: [(name: String, idValue: String)] = []
    var searchResult: (name: String, idValue: String)

    if json["hits"] != nil {
        let results:[AnyObject] = json["hits"]! as [AnyObject]
        for itemDictionary in results {
            let name:String? = (itemDictionary["fields"]? as NSDictionary)["item_name"] as? String
            let idValue:String? = itemDictionary["_id"]? as? String
            if (name? != nil && idValue? != nil) {
                searchResult = (name: name!, idValue: idValue!)
                usdaItemsSearchResults += [searchResult]
            }
        }
    }
    return usdaItemsSearchResults
}

Answer 1

已经解决了。该代码的工作原理如下。我进行了错误的深入研究。真的谢谢你，我学到了很多东西:

         class func jsonAsUSDAIdAndNameSearchResults (json: NSDictionary) -> [(name: String, idValue: String)] {

    var usdaItemsSearchResults: [(name: String, idValue: String)] = []
    var searchResult: (name: String, idValue: String)

    if json["hits"] != nil {
        let results:[AnyObject] = json["hits"]! as [AnyObject]
        for itemDictionary in results {

            let fields: NSDictionary = itemDictionary["fields"]? as NSDictionary
            let name:String? = fields["item_name"] as? String
            let idValue:String? = itemDictionary["_id"]? as? String
            if (name? != nil && idValue? != nil) {
                searchResult = (name: name!, idValue: idValue!)
                usdaItemsSearchResults += [searchResult]
            }
        }
    }
    return usdaItemsSearchResults
}