在Swift中过滤[AnyObject]的数组

Question

我AnyObject在Swift中有一个对象数组.每个对象都有一个餐馆的属性,例如名称,类型,位置等.如果我想保留数组中包含类型的所有对象:"Sushi",我如何过滤数组.

[AnyObject]包含2个对象的示例数组.过滤器应该保留第一个对象(类型:寿司):

[<Restaurant: 0x7ff302c8a4e0, objectId: LA74J92QDA, localId: (null)> {
    City = "New York";
    Country = "United States";
    Name = Sumo Japan;
    Type = Sushi, Japanese, Asian;
}, <Restaurant: 0x7ff302daa790, objectId: 0aKFrpKN46, localId: (null)> {
    City = "New York";
    Country = "United States";
    Name = Little Italy;
    Type = Italian, Pizza;
}]

当前代码(但我不确定过滤器是否可以搜索数组[AnyObject]):

var query = PFQuery(className:"Restaurant")
query.whereKey("RestaurantLoc", nearGeoPoint:userGeoPoint, withinMiles:50)
query.limit = 2
query.findObjectsInBackgroundWithBlock {
    (objects: [AnyObject]!, error: NSError!) -> Void in
    if objects != nil {
        println("list of objects of nearby")
        println(objects)
        let searchString = "Sushi"
        let predicate = NSPredicate(format: "Type CONTAINS[cd] %@", searchString);

        //Line below gives error: '[AnyObject]' does not have a member named 'filteredArrayUsingPredicate'
        //let filteredArray = objects.filteredArrayUsingPredicate(predicate!)

Answer 1

您的数组objects是一个PFObject对象数组.因此,对于filter数组,您可能会执行以下操作:

let filteredArray = objects.filter() {
    if let type = ($0 as PFObject)["Type"] as String {
        return type.rangeOfString("Sushi") != nil
    } else {
        return false
    }
}

基于我们处理自定义Restaurant对象的假设,我的原始答案如下:

您可以使用该filter方法.

我们假设Restaurant定义如下:

class Restaurant {
    var city: String
    var name: String
    var country: String
    var type: [String]!

    init (city: String, name: String, country: String, type: [String]!) {
        ...
    }
}

所以,假设这type是一个字符串数组,你可以这样做:

let filteredArray = objects.filter() {contains(($0 as Restaurant).type, "Sushi")}

如果您的类型数组可能是nil,您将对其进行条件展开:

let filteredArray = objects.filter() {
    if let type = ($0 as Restaurant).type as [String]! {
        return contains(type, "Sushi")
    } else {
        return false
    }
}

根据你的声明Restaurant,你没有与我们分享,细节会有所不同,但希望这说明了这个想法.

Answer 2

Swift 3解决方案

在数组上使用filter方法.

let restaurants: [Restaurants] = [...]
restaurants.filter({(restaurant) in
    return Bool(restaurant.type == "sushi")
})

或者return Bool(restaurant.type.contains("sushi"))如果type是一个数组.

Answer 3

好的,如果数组对象只包含Restaurant(s),则以下代码可以正常工作.

让我们说餐厅是这样的:

enum RestaurantType {
    case Sushi, Japanese, Asian
}

class Restaurant {
    var type = [RestaurantType]()
    // more properties here...
}

首先,我们定义一系列餐厅.

var restaurants = objects as [Restaurant]

然后我们可以过滤它:

var sushiRestaurants = restaurants.filter { (restaurant : Restaurant) -> Bool in
    return contains(restaurant.type, .Sushi)
}

Update: Now I am assuming objects is an array of PFObject(s) Just ignore my previous code and try this:

var restaurants = objects as [PFObject]
var sushiRestaurants = restaurants.filter { (restaurant : PFObject) -> Bool in
    return contains(restaurant["Type"], "Sushi")
}

Maybe it will crash again, the problem is that I don't know the type of Restaurant.Type. I'm trying. Maybe the next error message will provide more useful info.

Answer 4

将Rob的答案修改为Swift 2.0,在使用Rob的代码的swift 2.0中给出如下错误 -

initializer for conditional binding must have optional type, not 'string'

但是可以通过使用guard语句而不是if-let来解决它 -

let filteredArray = objects.filter() {
            guard let type = ($0 as PFObject)["Type"] as String else {
                return false
            } 
            return type.rangeOfString("Sushi") != nil
        }