TungVdMiichi

class TestGist {
  
}

TungVdMiichi

struct FeedItem {
  let title: String
  let thumbnailURL: URL
}

let items = [FeedItem(title: "title", thumbnailURL: URL(string: "http:a-url.com")!),
            FeedItem(title: "another title", thumbnailURL: URL(string: "http:b-url.com")!),
            FeedItem(title: "even another title", thumbnailURL: URL(string: "http:c-url.com")!),
            FeedItem(title: "even another another title", thumbnailURL: URL(string: "http:d-url.com")!)]

TungVdMiichi

var urls = [URL]()
for item in items {
  urls.append(item.thumbnailURL)
}

TungVdMiichi

let urls = items.map{$0.thumbnailURL}

TungVdMiichi

let urls = items.map { (item) -> URL in
    return item.thumbnailURL
}

TungVdMiichi

struct FeedItem {
  let title: String
  let thumbnailURL: URL?
}

let items = [FeedItem(title: "title", thumbnailURL: nil),
            FeedItem(title: "another title", thumbnailURL: URL(string: "http:b-url.com")!),
            FeedItem(title: "even another title", thumbnailURL: URL(string: "http:c-url.com")!),
            FeedItem(title: "even another another title", thumbnailURL: URL(string: "http:d-url.com")!)]

TungVdMiichi

var urls = [URL]()
for item in items {
    if let url = item.thumbnailURL {
        urls.append(url)
    }
}

TungVdMiichi

let urls = items.compactMap { (item) -> URL? in
    return item.thumbnailURL
}

// result: [http:b-url.com, http:c-url.com, http:d-url.com]

TungVdMiichi

let urls = items.compactMap { $0.thumbnailURL }

TungVdMiichi

struct FeedItem {
    let title: String
    let thumbnailURL: URL?
    let isFavorite: Bool
}

let items = [FeedItem(title: "title", thumbnailURL: nil, isFavorite: false),
             FeedItem(title: "another title", thumbnailURL: URL(string: "http:b-url.com")!, isFavorite: false),
             FeedItem(title: "even another title", thumbnailURL: URL(string: "http:c-url.com")!, isFavorite: true),
             FeedItem(title: "even another another title", thumbnailURL: URL(string: "http:d-url.com")!, isFavorite: true)]