刪除對象對象的字符串在一個單獨的陣列

Question

相匹配的字符串我有四根弦

class Post: NSObject { 
    var author: String! 
    var postID: String! 
    var pathToImage: String! 
    var userID: String! 
} 

一個NSObject I類也有一個單獨的類的ViewController具有抓取功能從火力職位。我有一個名爲posts = [Post]()的數組，其中填充了一個單獨的函數，通過firebase並獲取每張照片的數據。我也有一個名爲removeArray的數組，它是字符串數組，其中的字符串是某些帖子的postID。現在這是我的問題，我試圖通過removeArray循環，檢查removeArray =中的每一個是否與posts.postID中的每一個相同，並檢查它們是否相等。然後，我刪除每個在posts.postID後，或者我創建一個新的數組，這是post-postID的removeArray。這裏是我的代碼現在不起作用，它只是保持職位。

if posts != nil { 
    if var array = UserDefaults.standard.object(forKey: "removeArray") as? [String] { 
     for each in posts { 
      for one in array { 
       if one == each.postID { 
        new.append(each) 
       } 
      } 
     } 

     return self.posts.count 
    } 
} 

所以，如果你有任何想法如何採取一個字符串數組，檢查是否該字符串，如果eqaul到的objects.postID數組字符串，並從數組中刪除該對象是否相等。我試圖研究一種方法來過濾它，但到目前爲止沒有。請給我一些反饋。由於 我的問題= http://imgur.com/a/m5CiY

Answer 1

var posts = [p1,p2,p3,p4,p5] 
let array = ["aaa","bbb"] 
var new:Array<Post> = [] 

for each in posts { 
    for one in array { 
     if one == each.postID { 
      new.append(each) 
     } 
    } 
} 

print("This objects should be remvoed: \(new)") 
posts = Array(Set(posts).subtracting(new)) 
print("After removing matching objects: \(posts)") 

Answer 2

你可以使用reduce(_:_:)！

class Country { 

    var name: String! 

    init(name: String) { 

     self.name = name 
    } 
} 

let countries = [Country(name: "Norway"), Country(name: "Sweden"), Country(name: "Denmark"), Country(name: "Finland"), Country(name: "Iceland")] 

let scandinavianCountries = ["Norway", "Sweden", "Denmark"] 

// Store the objects you are removing here 
var nonScandinavianCountries: [Country]? 

let scandinavia = countries.reduce([Country](), { 
    result, country in 

    // Assign result to a temporary variable since result is immutable 
    var temp = result 

    // This if condition works as a filter between the countries array and the result of the reduce function. 
    if scandinavianCountries.contains(country.name) { 

     temp.append(country) 
    } else { 

     if nonScandinavianCountries == nil { 
      // We've reached a point where we need to allocate memory for the nonScandinavianContries array. Instantiate it before we append to it! 
      nonScandinavianCountries = [] 
     } 

     nonScandinavianCountries!.append(country) 
    } 

    return temp 
}) 

scandinavia.count // 3 

nonScandinavianCountries?.count // 2 

Resouces： https://developer.apple.com/reference/swift/array/2298686-reduce