Swift投射
示例
将函数应用于集合/流并创建新的集合/流称为投影。
///投影
var newReleases = [
[
"id": 70111470,
"title": "Die Hard",
"boxart": "http://cdn-0.nflximg.com/images/2891/DieHard.jpg",
"uri": "http://api.netflix.com/catalog/titles/movies/70111470",
"rating": [4.0],
"bookmark": []
],
[
"id": 654356453,
"title": "Bad Boys",
"boxart": "http://cdn-0.nflximg.com/images/2891/BadBoys.jpg",
"uri": "http://api.netflix.com/catalog/titles/movies/70111470",
"rating": [5.0],
"bookmark": [[ "id": 432534, "time": 65876586 ]]
],
[
"id": 65432445,
"title": "The Chamber",
"boxart": "http://cdn-0.nflximg.com/images/2891/TheChamber.jpg",
"uri": "http://api.netflix.com/catalog/titles/movies/70111470",
"rating": [4.0],
"bookmark": []
],
[
"id": 675465,
"title": "Fracture",
"boxart": "http://cdn-0.nflximg.com/images/2891/Fracture.jpg",
"uri": "http://api.netflix.com/catalog/titles/movies/70111470",
"rating": [5.0],
"bookmark": [[ "id": 432534, "time": 65876586 ]]
]
]
var videoAndTitlePairs = [[String: AnyObject]]()
newReleases.map { e in
videoAndTitlePairs.append(["id": e["id"] as! Int, "title": e["title"] as! String])
}
print(videoAndTitlePairs)