删除对象对象的字符串在一个单独的阵列

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! 
} 

一个NSObject I类也有一个单独的类的ViewController具有抓取功能从火力职位。我有一个名为posts = [Post]()的数组，其中填充了一个单独的函数，通过firebase并获取每张照片的数据。我也有一个名为removeArray的数组，它是字符串数组，其中的字符串是某些帖子的postID。现在这是我的问题，我试图通过removeArray循环，检查removeArray =中的每一个是否与posts.postID中的每一个相同，并检查它们是否相等。然后，我删除每个在posts.postID后，或者我创建一个新的数组，这是post-postID的removeArray。这里是我的代码现在不起作用，它只是保持职位。

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采取一个字符串数组，检查是否该字符串，如果eqaul到的objects.postID数组字符串，并从数组中删除该对象是否相等。我试图研究一种方法来过滤它，但到目前为止没有。请给我一些反馈。由于 我的问题= 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