title: iOS Charts(Daniel Gindi) - how to set dual y axis dual graph lines in Swift
body: <p>I am using <a href="https://github.com/danielgindi/Charts" rel="nofollow noreferrer">Charts (Git Repo of Daniel Gindi's)</a>. Here is my code for single y axis single line chart: When I try to add a second line to the y axis it throws the error 'Cannot convert value of type 'LineChartDataSet' to expected argument type 'String''</p>
  
  <pre><code>import UIKit
  import Charts
  
  class PulseController: UIViewController, ChartViewDelegate {
  
      @IBOutlet var lineChartView: LineChartView!
  
      override func viewDidLoad() {
          super.viewDidLoad()
  
          let months = ["Jan", "Feb", "Mar", "Apr", "May", "Jun"]
          let unitsSold = [20.0, 4.0, 6.0, 3.0, 12.0, 16.0]
  
          setChart(months, values: unitsSold)
      }
  
      func setChart(dataPoints: [String], values: [Double]) {
  
          var dataEntries: [ChartDataEntry] = []
  
          for i in 0..&lt;dataPoints.count {
              let dataEntry = ChartDataEntry(value: values[i], xIndex: i)
              dataEntries.append(dataEntry)
          }
  
          let lineChartDataSet = LineChartDataSet(yVals: dataEntries, label: "Pulse")
          let lineChartData = LineChartData(xVals: dataPoints, dataSet: lineChartDataSet)
          lineChartView.data = lineChartData
  
          lineChartView.animate(xAxisDuration: 2.0)
          lineChartView.animate(yAxisDuration: 2.5)
  
          lineChartDataSet.setCircleColor(UIColor.init(red: 14/255, green: 165/255, blue: 150/255, alpha: 1))
  
          lineChartDataSet.setColor(UIColor.init(red: 14/255, green: 165/255, blue: 150/255, alpha: 1))
      }
  }
  </code></pre>