为什么错误：致命错误：数组索引超出范围？ [迅速]

Question

请在下图中找到错误位置：

tripOption中的值数量将在每个请求中更改。

在代码中有一个逻辑问题，例如tripOption只输出2个值..但是循环继续并且表示数组超出索引..我不知道如何解决这个问题。

 var arrayOfFlights : [FlightDataModel] = [FlightDataModel]()

        if json != nil {

            //insert airline data into arrayOfFlights
            if let myJSON = json as? [String:AnyObject] {
                if let trips = myJSON["trips"] as? [String:AnyObject] {
                    if let data = trips["data"] as? [String:AnyObject] {

                        if let carriers = data["carrier"] as? [[String:String]] {
                            for (index, carrierName) in enumerate(carriers) {

                                var myFlight = FlightDataModel(airline: carrierName["name"] as String!, price:nil)
                                self.arrayOfFlights.append(myFlight)

                                println("\(self.arrayOfFlights[index].airline!)")

                            }
                        }
                    }

                    if var tripOptions = trips["tripOption"] as? [[String:String]] {

                        for (index, tripOption) in enumerate(tripOptions) {

                            self.arrayOfFlights[index].price = tripOption["saleTotal"] as String!

                          println("price \(self.arrayOfFlights[index].price!)")

                        }

                    }
                }
            }

url jsjon请求中的参数：

var parameters = [
    "request": [
        "slice": [
            [
                "origin": from,
                "destination": to,
                "date": when
            ]
        ],

        "passengers": [
            "adultCount": 1,
            "infantInLapCount": 0,
            "infantInSeatCount": 0,
            "childCount": 0,
            "seniorCount": 0
        ],

        "solutions": 5,
        "refundable": false

    ]
]

Answer 1

该错误是因为您尝试访问arrayOfFlights中索引大于其size - 1的元素。

Answer 2

// index > no of existing elements in the array
self.arrayOfFlights[index].price = tripOption["saleTotal"] as String!

也许您正在尝试将新元素推送到空数组中？

self.arrayOfFlightPrices.append(tripOption["saleTotal"] as String!)

Answer 3

您应该简化代码并使用结果的第一次迭代来确保您不会超出范围。像这样的东西：

var arrayOfFlights : [FlightDataModel] = [FlightDataModel]()

    if let data = json as? NSDictionary {

        if let carriers = data.valueForKeyPath("trips.data.carrier") as? NSArray {
            for (index, carrier) in enumerate(carriers) {
                var myFlight = FlightDataModel(airline: carrier["name"] as String!, price:nil)
                arrayOfFlights.append(myFlight)
            }
        }

        if let trips = data.valueForKey("trips") as? NSArray where arrayOfFlights.count > 0 {
            for (index, carrier) in enumerate(arrayOfFlights) {
                carrier.price = trips.objectAtIndex(index)["saleTotal"] as String!                    
            }
        }
    }