Question

当尝试获取子数组时，给定范围此错误。

Cannot subscript a value of type '[Info]' with an index of type 'CountableRange<Int>' .

我的代码是

信息模式

class Info : NSObject {
    var type : Type = .Unknown
    var data = ""

    init() {
        super.init()
    }
}

数组声明

var currentData : [Info] = []

尝试此代码时

let moreAnimals: [Info] = self.currentData[0..<5] //above error disply.

Answer 1

let currentData = [Info(), Info(), Info()]
let subarr0 = currentData[0..<2] // ArraySlice<Info>
let subarr1 = Array(currentData[0..<2]) // Array<Info>

Answer 2

从泛型集合中获取元素范围，我们需要转换为NSArray并使用subarrayWithRange方法获取范围内的元素。

var moreAnimals: [Int] = [1,2,3,4,5,6,7,8,9,10]

var otherarr: [Int] = (moreAnimals as NSArray).subarray(with: NSMakeRange(0, 5)) as! [Int]

输出:: [1,2,3,4,5,6,7,8,9,10]

[1,2,3,4,5]

尝试使用给定范围获取子数组

2 个答案: