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)