ios - Swift如何访问嵌套结构中的信息？

Question

我有一个带有主题和子主题信息的大嵌套结构数据文件。

struct Topic{
    struct Topic1{
      let name = "Topic 1"
        let description = "Topic 1 description here."

        struct SubtopicUniqueName1 {
            let title = "Subtopic title here." 
            let subtopicDescription = "Some lorem ipsum description...."
            let subtopicContent = ["First Sentence", "Second Sentence", "Hello"]
        }

        struct SubtopicUniqueName2 {
            let title = "Subtopic title here." 
            let subtopicDescription = "Some lorem ipsum description...."
            let subtopicContent = ["First Sentence", "Second Sentence", "Hello"]
        }
    }

    struct Topic2{
        let name = "Topic 2"
        let description = "Topic 2 description here."
        struct SubtopicUniqueName3 {
            let title = "Subtopic title here." 
            let subtopicDescription = "Some lorem ipsum description...."
            let subtopicContent = ["First Sentence", "Second Sentence", "Hello"]
        }
    }
}

我想得到一个包含Topic1，Topic2等所有“名称”的数组，以此类推，因为最后我将有多达14个主题。当我尝试 let allTopics = [Topic.Topic1, Topic.Topic2]时它将无法运行

我想通过做类似的事情来获取信息

for i in allTopics{
   print(i().name)
}

最后，由于Subtopics结构进一步嵌套，我是否可以在Topic中以类似的方式访问其内容？

Answer 1

您会混淆值和类型。在这里，您实际上只有两种类型:主题和子主题。因此，让他们:

struct Topic {
    let name: String
    let description: String
    let subTopics: [SubTopic]
}

struct SubTopic {
    let title: String
    let description: String
    let content: [String]
}

其他所有内容只是这两种类型之一的实例:

let topics = [
    Topic(
        name: "Topic 1",
        description: "Topic 1 description here.",
        subTopics: [
            SubTopic(
                title: "Subtopic title here.",
                description: "Some lorem ipsum description...",
                content: ["First Sentence", "Second Sentence", "Hello"]
            ),
            SubTopic(
                title: "Subtopic title here.",
                description: "Some lorem ipsum description...",
                content: ["First Sentence", "Second Sentence", "Hello"]
            ),
        ]
    ),
    Topic(
        name: "Topic 2",
        description: "Topic 2 description here.",
        subTopics: [
            SubTopic(
                title: "Subtopic title here.",
                description: "Some lorem ipsum description...",
                content: ["First Sentence", "Second Sentence", "Hello"]
            ),
        ]
    ),
]

由于这些只是常规数组，因此您可以轻松地对其进行迭代:

for topic in topics {
    print("\(topic.name) - \(topic.description)")
    print()

    for subTopic in topic.subTopics {
        let content = subTopic.content.joined(separator: "\n\t")
        print("""
            \(subTopic.title) - \(subTopic.description)
            \(content)

        """)
    }
}

输出:

Topic 1 - Topic 1 description here.

    Subtopic title here. - Some lorem ipsum description...
    First Sentence
    Second Sentence
    Hello

    Subtopic title here. - Some lorem ipsum description...
    First Sentence
    Second Sentence
    Hello

Topic 2 - Topic 2 description here.

    Subtopic title here. - Some lorem ipsum description...
    First Sentence
    Second Sentence
    Hello