打印不顯示在控制檯中（swift）

Question

我的代碼不能在控制檯中打印。我嘗試了一些方法，但沒有任何工作。下面的代碼是完整版本的代碼，可能會導致打印不顯示在控制檯中的原因。請幫我找出這個小問題。我試圖儘可能多的方法來調試這個問題，但無濟於事。

這是我的代碼：

import Foundation 

// Function to calculate the arithmetic mean 

func arithmeticMean(array: [Double]) -> Double { 
    var total: Double = 0 
    for number in array { 
     total += number 
    } 
    return total/Double(array.count) 
} 

// Function to calculate the standard deviation 

func standardDeviation(array: [Double]) -> Double 
{ 
    let length = Double(array.count) 
    let avg = array.reduce(0, {$0 + $1})/length 
    let sumOfSquaredAvgDiff = array.map { pow($0 - avg, 2.0)}.reduce(0, {$0 + $1}) 
    return sqrt(sumOfSquaredAvgDiff/length) 
} 

// Function to extract some range from an array 

func subArray<T>(array: [T], s: Int, e: Int) -> [T] { 
    if e > array.count { 
     return [] 
    } 
    return Array(array[s..<min(e, array.count)]) 
} 

// Smooth z-score thresholding filter 

func ThresholdingAlgo(y: [Double],lag: Int,threshold: Double,influence: Double) -> ([Int],[Double],[Double]) { 

    // Create arrays 
    var signals = Array(repeating: 0, count: y.count) 
    var filteredY = Array(repeating: 0.0, count: y.count) 
    var avgFilter = Array(repeating: 0.0, count: y.count) 
    var stdFilter = Array(repeating: 0.0, count: y.count) 

    // Initialise variables 
    for i in 0...lag-1 { 
     signals[i] = 0 
     filteredY[i] = y[i] 
    } 

    // Start filter 
    avgFilter[lag-1] = arithmeticMean(array: subArray(array: y, s: 0, e: lag-1)) 
    stdFilter[lag-1] = standardDeviation(array: subArray(array: y, s: 0, e: lag-1)) 

    for i in lag...y.count-1 { 
     if abs(y[i] - avgFilter[i-1]) > threshold*stdFilter[i-1] { 
      if y[i] > avgFilter[i-1] { 
       signals[i] = 1  // Positive signal 
      } else { 
       // Negative signals are turned off for this application 
       signals[i] = -1  // Negative signal 
      } 
      filteredY[i] = influence*y[i] + (1-influence)*filteredY[i-1] 
     } else { 
      signals[i] = 0   // No signal 
      filteredY[i] = y[i] 
     } 
     // Adjust the filters 
     avgFilter[i] = arithmeticMean(array: subArray(array: filteredY, s: i-lag, e: i)) 
     stdFilter[i] = standardDeviation(array: subArray(array: filteredY, s: i-lag, e: i)) 
    } 
    return (signals,avgFilter,stdFilter) 
} 


func viewDidLoad() 
{ 

// Demo 

let samples = [0.01, -0.02, -0.02, 0.01, -0.01, -0.01, 0.00, 0.10, 0.31, 
       -0.10, -0.73, -0.68, 0.21, 1.22, 0.67, -0.59, -1.04, 0.06, 0.42, 0.07, 
       0.03, -0.18, 0.11, -0.06, -0.02, 0.16, 0.21, 0.03, -0.68, -0.89, 0.18, 
       1.31, 0.66, 0.07, -1.62, -0.16, 0.67, 0.19, -0.42, 0.23, -0.05, -0.01, 
       0.03, 0.06, 0.27, 0.15, -0.50, -1.18, 0.11, 1.30, 0.93, 0.16, -1.32, 
       -0.10, 0.55, 0.23, -0.03, -0.23, 0.16, -0.04, 0.01, 0.12, 0.35, -0.38, 
       -1.11, 0.07, 1.46, 0.61, -0.68, -1.16, 0.29, 0.54, -0.05, 0.02, -0.01, 
       0.12, 0.23, 0.29, -0.75, -0.95, 0.11, 1.51, 0.70, -0.30, -1.48, 0.13, 
       0.50, 0.18, -0.06, -0.01, -0.02, 0.03, -0.02, 0.06, 0.03, 0.03, 0.02, 
       -0.01, 0.01, 0.02, 0.01] 

// Run filter 

let (signals,avgFilter,stdFilter) = ThresholdingAlgo(y: samples, lag: 10, threshold: 3, influence: 0.2) 

// Print output to console 
print("\nOutput: \n ") 

    for i in 0...signals.count - 1 
    { 
     print("Data point \(i)\t\t sample: \(samples[i]) \t signal: \(signals[i])\n") 
    } 

    // Raw data for creating a plot in Excel 
    print("\n \n Raw data for creating a plot in Excel: \n ") 
    for i in 0...signals.count - 1 
    { 
     print("\(i+1)\t\(samples[i])\t\(signals[i])\t\(avgFilter[i])\t\(stdFilter[i])\n") 
    } 
} 

你的幫助深表感謝！我已經在整個代碼中添加了，所以這可能有助於調試問題。

Answer 1

可能信號數組是空的，所以循環不會被執行。 也許你想把「samples.cout-1」而不是「信號」？

Answer 2

好吧，也許我發現你的問題。函數viewDidLoad不在任何類中，並且不覆蓋任何委託方法。這意味着它不會在視圖出現時自動調用。

例

class ViewController: UIViewController { 

override func viewDidLoad() { 
    super.viewDidLoad() // the view did load gets called when view appears 
    // Do any additional setup after loading the view, typically from a nib. 
} 
} 

在這種情況下，當顯示我們的類加載的觀點，但你的功能viewDidLoad沒有任何類中。