如何在Swift中获取多层嵌套字典内的指定数据

• MV["Nobody"]报错：MV的类型是[[String: [[String: Any]]]]，最外层是数组，仅支持整数下标访问，无法直接用字符串作为下标取值
• 遍历代码报错：MV的每一个元素是仅包含单个键值对的字典，不是元组，需要先取出每个字典的key和value再处理，正确遍历写法如下：

for movieItem in MV {
    guard let movieName = movieItem.keys.first, let movieData = movieItem[movieName] else { continue }
    print("电影名：\(movieName)")
    print("电影数据：\(movieData)")
}

1. 获取电影"Nobody"对应的"IMAGE"值 #

// 首先从外层数组筛选出Nobody对应的所有属性
guard let nobodyAttrs = MV.first(where: { $0.keys.contains("Nobody") })?["Nobody"] else {
    print("未找到电影Nobody的相关数据")
    exit(0)
}
// 从属性数组中筛选IMAGE对应的键值对
if let imageAttr = nobodyAttrs.first(where: { $0.keys.contains("IMAGE") }),
   let imageName = imageAttr["IMAGE"] as? String {
    print(imageName) // 输出：Nobody.png
}

2. 获取BestMoments的成员数量 #

// 获取Nobody的BestMoments数量
if let momentsAttr = nobodyAttrs.first(where: { $0.keys.contains("BestMoments") }),
   let momentsList = momentsAttr["BestMoments"] as? [Any] {
    print(momentsList.count) // 输出：3
}

// 获取Godzilla vs. Kong的BestMoments数量
guard let kongAttrs = MV.first(where: { $0.keys.contains("Godzilla vs. Kong") })?["Godzilla vs. Kong"],
      let kongMomentsAttr = kongAttrs.first(where: { $0.keys.contains("BestMoments") }),
      let kongMomentsList = kongMomentsAttr["BestMoments"] as? [Any] else {
    print("未找到对应电影数据")
    exit(0)
}
print(kongMomentsList.count) // 输出：4

3. 获取"Nobody"对应BestMoments内的"Survive"组数据 #

if let momentsAttr = nobodyAttrs.first(where: { $0.keys.contains("BestMoments") }),
   let momentsList = momentsAttr["BestMoments"] as? [[Any]] {
    // 筛选首个元素为Survive的数组
    guard let surviveItem = momentsList.first(where: { $0.first as? String == "Survive" }) else {
        print("未找到对应数据")
        exit(0)
    }
    print(surviveItem) // 输出：["Survive", 120, 8]
    // 可通过下标单独取值：surviveItem[0]为"Survive"，surviveItem[1]为120，surviveItem[2]为8
}

你当前的数组套单键字典的结构访问效率很低，建议调整为外层是字典，key为电影名，value为该电影的属性字典，优化后结构及访问方式如下：

var optimizedMV: [String: [String: Any]] = [
    "Nobody": [
        "YEAR" : "2021",
        "IMAGE" : "Nobody.png",
        "GENRE" : "Action/Thriller",
        "DURATIONhours" : 1,
        "DURATIONmintues" : 36,
        "DURATIONseconds" : 17,
        "BestMoments" : [["Win", 25, 5], ["Survive", 120, 8], ["Lose", 240, 15]]
    ],
    "Godzilla vs. Kong": [
        "YEAR" : "2021",
        "IMAGE" : "GodzillaVsKong.png",
        "GENRE" : "Action/Sci-fi",
        "DURATIONhours" : 1,
        "DURATIONmintues" : 22,
        "DURATIONseconds" : 45,
        "BestMoments" : [["Win", 34, 6], ["Survive", 120, 8], ["Twist", 233, 3], ["Lose", 340, 12]]
    ]
]

// 优化后直接通过key取值即可
// 取IMAGE值
print(optimizedMV["Nobody"]?["IMAGE"] as? String ?? "")
// 取BestMoments数量
print((optimizedMV["Nobody"]?["BestMoments"] as? [Any])?.count ?? 0)
// 取Survive组数据
let moments = optimizedMV["Nobody"]?["BestMoments"] as? [[Any]] ?? []
let surviveItem = moments.first { $0.first as? String == "Survive" }

内容的提问来源于stack exchange，提问作者ooenomel2003