Swift：使用 UUID 从数组中删除重复对象

Question

我正在使用 UUID 来使用 DiffableDataSource，但我正在使用的数据集包含每个对象的副本。

这是我在操场上使用的代码示例：

var movies: [MovieSearch] = []

struct MovieSearch: Hashable, Decodable, Equatable {
    let uuid = UUID()
    private enum CodingKeys : String, CodingKey { case Name, StartDate }
    
    let Name: String
    let StartDate: String
}
    
movies = [
  MovieSearch(Name: "Blade Runner", StartDate: "01/01/2021"), 
  MovieSearch(Name: "Blade Runner: 2049", StartDate: "01/07/2021"),     
  MovieSearch(Name: "UBIK", StartDate: "01/14/2021"),    
  MovieSearch(Name: "Blade Runner", StartDate: "01/01/2021"),    
  MovieSearch(Name: "Blade Runner: 2049", StartDate: "01/07/2021"),    
  MovieSearch(Name: "UBIK", StartDate: "01/14/2021")    
]

由于在初始化时添加了 UUID，在这种情况下是否有合理的方法来删除重复项？

Answer 1

如果您不关心电影的顺序，可以使用 Swift 的 Set。

由于您的MovieSearch 符合 Hashable 协议，因此 Set 将确保仅存在一个副本。

您可以使用 for-in 表示法遍历 Set，类似于数组。

https://developer.apple.com/documentation/swift/set

struct MovieSearch: Hashable, Decodable, Equatable {
    let uuid = UUID()
    private enum CodingKeys : String, CodingKey { case Name, StartDate }
    
    let Name: String
    let StartDate: String
}
    
var movies:Set = [
  MovieSearch(Name: "Blade Runner", StartDate: "01/01/2021"), 
  MovieSearch(Name: "Blade Runner: 2049", StartDate: "01/07/2021"),     
  MovieSearch(Name: "UBIK", StartDate: "01/14/2021"),    
  MovieSearch(Name: "Blade Runner", StartDate: "01/01/2021"),    
  MovieSearch(Name: "Blade Runner: 2049", StartDate: "01/07/2021"),    
  MovieSearch(Name: "UBIK", StartDate: "01/14/2021")    
]

for movie in movies {
   print(movie.Name)
}

Answer 2

所以我猜你想要做的是删除那些重复项？

然后编写一个函数，根据电影的名称（我猜是唯一的）删除重复项并使用它来过滤。

func removeDup(movies: [MovieSearch]) -> [MovieSearch] {
    var uniqueMovies = Set<String>()
    var moviesWithoutDups = [MovieSearch]()
    
    for movie in movies {
        if !uniqueMovies.contains(movie.name) {
            moviesWithoutDups.append(movie)
            uniqueMovies.insert(movie.name)
        }
    }
    return moviesWithoutDups
}

然后使用函数：

movies = removeDup(movies: movies)