# 2020-04-06 | IA | DataPreparation

###### tags: `swift` `ia` `gobelins`

## Class

import Foundation

class DataPreparation {

    enum CoordOrganization {
        case pair,seq
    }

    var values = [Double]()
    var org:CoordOrganization

    init(array:[Double],org:CoordOrganization = .pair){
        self.values = array
        self.org = org
    }

    init(array:[CGPoint],org:CoordOrganization = .pair) {
        // TO DO erreur si != de pair
        if org != .pair {
            print("/.pair/ Coming soon...")
        }
        self.org = org
        self.values = convert(coords:array, org:self.org)

    }
}

extension DataPreparation {
    // mean
    func calcArrayMean() -> [Double] {

        var sums:[Double] = [0.0,0.0]

        for i in 0..<self.values.count {
            sums[i % 2] += self.values[i]
        }

        var meanArray = sums.map{
            $0 / (Double(self.values.count) / 2.0)
        }
        return meanArray
    }

}

extension DataPreparation {
    // normalize
    private func convert(coords:[CGPoint], org:CoordOrganization) -> [Double] {

        var values = [Double]()

        switch org {
            case .pair:
                values = getCGPointToDoubleCouple(pos:coords)
            case .seq:
                values = getCGPointToDouble(pos:coords)
        }

        return values
    }

    func normalize() -> [Double] {
        let min = self.values.min()!
        let max = self.values.max()!

        var finalArray = [Double]()

        if min == max {
            for item in values {
                finalArray.append(1.0 / Double(self.values.count))
            }
        }else{
            finalArray = self.values.map{($0 - min)/(max - min)}
        }

        return finalArray
    }

    func formatArray(n:Int) -> [Double]{
        var finalArray = [Double]()

        for i in 0..<n{
            if i < self.values.count {
                finalArray.append(self.values[i])
            }
            else{
                finalArray.append(0.0)
            }
        }

        return finalArray
    }

    private func getCGPointToDouble(pos:[CGPoint]) -> [Double] {
        var values = [Double]()
        
        var coordX = [Double]()
        var coordY = [Double]()

        coordX = pos.map{Double($0.x)}
        coordY = pos.map{Double($0.y)}

        values = coordX + coordY

        return values
    }

    private func getCGPointToDoubleCouple(pos:[CGPoint]) -> [Double] {
        var values = [Double]()
        
        var t = pos.map{[Double($0.x),Double($0.y)]}
        values = t.flatMap{$0}

        return values
    }

    // standardisation
     func standardization() -> [Double] {
        var means:[Double] = self.calcArrayMean()
        var standardDeviations:[Double] = self.calcStandardDeviation(means:means)

        var standardizedArray = self.values.enumerated().map{
            ($0.element - means[$0.offset % 2] ) / standardDeviations[$0.offset % 2] 
        }
        
        return standardizedArray
    }

    private func calcStandardDeviation(means:[Double]) -> [Double]{

        var sums:[Double] = [0.0,0.0]
        var deviations = [Double]()

        for i in 0..<self.values.count {
            sums[i % 2] += pow(self.values[i] - means[i % 2], 2.0)
        }   

        deviations = sums.map{
            sqrt($0 / (Double(self.values.count) / 2.0)) 
        }
        
        return deviations
    }
}

## How to use

var pos = [CGPoint(x: 0, y: 1),CGPoint(x: 2, y: 5),CGPoint(x: 4, y: 1),CGPoint(x: 1, y: 0),CGPoint(x: 4, y: 9),CGPoint(x: 0, y: 1),CGPoint(x: 2, y: 5),CGPoint(x: 4, y: 1),CGPoint(x: 1, y: 0),CGPoint(x: 4, y: 9),CGPoint(x: 0, y: 1),CGPoint(x: 2, y: 5),CGPoint(x: 4, y: 1),CGPoint(x: 1, y: 0),CGPoint(x: 4, y: 9),CGPoint(x: 0, y: 1),CGPoint(x: 2, y: 5),CGPoint(x: 4, y: 1),CGPoint(x: 1, y: 0),CGPoint(x: 4, y: 9)]
var posDouble = [0.0,1.0,2.0,5.0,4.0,1.0,1.0,0.0,4.0,9.0,0.0,1.0,2.0,5.0,4.0,1.0,1.0,0.0,4.0,9.0,0.0,1.0,2.0,5.0,4.0,1.0,1.0,0.0,4.0,9.0,0.0,1.0,2.0,5.0,4.0,1.0,1.0,0.0,4.0,9.0]

print("Data CGPoint")
let data = DataPreparation(array:pos)
print(data.normalize())
print(data.formatArray(n:50))
print(data.calcArrayMean())

print("Data Double")
let dataDouble = DataPreparation(array:posDouble)
print(dataDouble.normalize())
print(data.formatArray(n:5))
print(dataDouble.calcArrayMean())

## Result

Data CGPoint
[0.0, 0.1111111111111111, 0.2222222222222222, 0.5555555555555556, 0.4444444444444444, 0.1111111111111111, 0.1111111111111111, 0.0, 0.4444444444444444, 1.0, 0.0, 0.1111111111111111, 0.2222222222222222, 0.5555555555555556, 0.4444444444444444, 0.1111111111111111, 0.1111111111111111, 0.0, 0.4444444444444444, 1.0, 0.0, 0.1111111111111111, 0.2222222222222222, 0.5555555555555556, 0.4444444444444444, 0.1111111111111111, 0.1111111111111111, 0.0, 0.4444444444444444, 1.0, 0.0, 0.1111111111111111, 0.2222222222222222, 0.5555555555555556, 0.4444444444444444, 0.1111111111111111, 0.1111111111111111, 0.0, 0.4444444444444444, 1.0]
[0.0, 1.0, 2.0, 5.0, 4.0, 1.0, 1.0, 0.0, 4.0, 9.0, 0.0, 1.0, 2.0, 5.0, 4.0, 1.0, 1.0, 0.0, 4.0, 9.0, 0.0, 1.0, 2.0, 5.0, 4.0, 1.0, 1.0, 0.0, 4.0, 9.0, 0.0, 1.0, 2.0, 5.0, 4.0, 1.0, 1.0, 0.0, 4.0, 9.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0]
[2.2, 3.2]
Data Double
[0.0, 0.1111111111111111, 0.2222222222222222, 0.5555555555555556, 0.4444444444444444, 0.1111111111111111, 0.1111111111111111, 0.0, 0.4444444444444444, 1.0, 0.0, 0.1111111111111111, 0.2222222222222222, 0.5555555555555556, 0.4444444444444444, 0.1111111111111111, 0.1111111111111111, 0.0, 0.4444444444444444, 1.0, 0.0, 0.1111111111111111, 0.2222222222222222, 0.5555555555555556, 0.4444444444444444, 0.1111111111111111, 0.1111111111111111, 0.0, 0.4444444444444444, 1.0, 0.0, 0.1111111111111111, 0.2222222222222222, 0.5555555555555556, 0.4444444444444444, 0.1111111111111111, 0.1111111111111111, 0.0, 0.4444444444444444, 1.0]
[0.0, 1.0, 2.0, 5.0, 4.0]
[2.2, 3.2]