ios - 访问特定索引中的数组

Question

我正在尝试访问函数中的数组，据我所知，Swift 中没有 Arraylists，因此我正在尝试使用常规列表:

  func findNearsetPoints(pointsArray: [Point] , myPoint: Point )-> Array <Point>{

    var twoPoint = [Point]()
    var minDist1:Double = DBL_MAX;
    var minDist2:Double = DBL_MAX;
    var distance:Double = 0

    for element in pointsArray{
        distance = getDistanceBetweenTwoPoints(pointsArray[element], Point); //error 0
        if (distance < minDist1) {
            minDist1 = distance;
            twoPoint[1] = twoPoint[0];
            twoPoint[0] = pointsArray[element]; // error 1
        }
        else if (distance < minDist2) {
            minDist2 = distance;
            twoPoint[1] = pointsArray[element]; //error 1
        }
    }

    return twoPoint;
    }

    func getDistanceBetweenTwoPoints(point1:Point , point2:Point )->Double{
        return 5; //TODO
    }

错误 0:

/Users/user/Desktop/proj/ViewController.swift:145:38: Cannot subscript a value of type '[ViewController.Point]' with an index of type 'ViewController.Point'

错误一:

/Users/user/Desktop/proj/ViewController.swift:149:38: Cannot subscript a value of type '[ViewController.Point]' with an index of type 'ViewController.Point'

代码有什么问题？谢谢!

Answer 1

您的 element 已经是一个 Point 而不是索引。

for element in pointsArray{
    distance = getDistanceBetweenTwoPoints(point1: element, point2: myPoint) // fix here
    if (distance < minDist1) {
        minDist1 = distance;
        twoPoint[1] = twoPoint[0];
        twoPoint[0] = element; // fix here
    }
    else if (distance < minDist2) {
        minDist2 = distance;
        twoPoint[1] = element; // fix here
    }
}

附言:也看看this question "Sort array by calculated distance in Swift"为了更好地计算距离。只需按距离对数组进行排序，然后在排序后从数组中取出第一个。那更容易做到