制作阵列斯威夫特我的函数计算平均 [英] Making my function calculate average of array Swift

问题描述

我希望我的函数来计算我的双类型的数组的平均值。该阵列被称为内容。现在，我有10个号码。

I want my function to calculate the average of my Double type array. The array is called "votes". For now, I have 10 numbers.

当我称之为平均函数来得到数组票平均水平，这是行不通的。

When I call the average function to get the average of the array votes, it doesn't work.

下面是我的code：

var votes = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

func average(nums: Double...) -> Double {
  var total = 0.0

  for vote in votes {
    total += vote
  }
  let votesTotal = Double(votes.count)
  var average = total/votesTotal
  return average
  }

average[votes]

我怎么在这里所说的平均获得平均？

How do I call the average here to get the average?

推荐答案

您应该使用减少（）方法来总结您的数组如下：

You should use the reduce() method to sum your array as follow:

let votes:[Double] = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
let votesAvg = votes.reduce(0, combine: +) / Double(votes.count)
println( votesAvg )    // "5.5"

更新： X $ C $ 7.3Ç雨燕•2.2

您还可以扩展延伸斯威夫特 _ArrayType 议定书阵列的只是一个特定类型返回其元素平均如下：

You can also extend just a specific type of array extending Swift _ArrayType Protocol to return its elements average as follow:

extension _ArrayType where Generator.Element == Int {
    var total: Int {
        guard !isEmpty else { return 0 }
        return reduce(0, combine: +)
    }
    var average: Double {
        return Double(total)/Double(count)
    }
}

extension _ArrayType where Generator.Element == Double {
    var total: Double {
        guard !isEmpty else { return 0 }
        return  reduce(0, combine: +)
    }
    var average: Double {
        guard !isEmpty else { return 0 }
        return  total / Double(count)
    }
}

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