Remove misuse of count

Source/Charts/Charts/ChartViewBase.swift

@@ -312,7 +312,7 @@ open class ChartViewBase: NSUIView, ChartDataProvider, AnimatorDelegate
         guard
             description.isEnabled,
             let descriptionText = description.text,
-            descriptionText.count > 0
+            !descriptionText.isEmpty
             else { return }
 
         let position = description.position ?? CGPoint(x: bounds.width - viewPortHandler.offsetRight - description.xOffset,

Source/Charts/Charts/CombinedChartView.swift

@@ -213,7 +213,7 @@ open class CombinedChartView: BarLineChartViewBase, CombinedChartDataProvider
             isDrawMarkersEnabled && valuesToHighlight()
             else { return }
 
-        for i in 0 ..< highlighted.count
+        for i in highlighted.indices
         {
             let highlight = highlighted[i]
 

Source/Charts/Charts/PieRadarChartViewBase.swift

@@ -678,7 +678,6 @@ open class PieRadarChartViewBase: ChartViewBase
 
         // Remove samples older than our sample time - 1 seconds
         // while keeping at least one sample
-
         var i = 0, count = velocitySamples.count
         while (i < count - 2)
         {

Source/Charts/Components/AxisBase.swift

@@ -135,7 +135,7 @@ open class AxisBase: ComponentBase
     {
         var longest = ""
 
-        for i in 0 ..< entries.count
+        for i in entries.indices
         {
             let text = getFormattedLabel(i)
 
@@ -151,10 +151,7 @@ open class AxisBase: ComponentBase
     /// - Returns: The formatted label at the specified index. This will either use the auto-formatter or the custom formatter (if one is set).
     @objc open func getFormattedLabel(_ index: Int) -> String
     {
-        if index < 0 || index >= entries.count
-        {
-            return ""
-        }
+        guard entries.indices.contains(index) else { return "" }
 
         return valueFormatter?.stringForValue(entries[index], axis: self) ?? ""
     }

Source/Charts/Components/Legend.swift

@@ -229,7 +229,7 @@ open class Legend: ComponentBase
 
             var wasStacked = false
 
-            for i in 0 ..< entryCount
+            for i in entries.indices
             {
                 let e = entries[i]
                 let drawingForm = e.form != .none
@@ -311,7 +311,7 @@ open class Legend: ComponentBase
             var requiredWidth: CGFloat = 0.0
             var stackedStartIndex: Int = -1
 
-            for i in 0 ..< entryCount
+            for i in entries.indices
             {
                 let e = entries[i]
                 let drawingForm = e.form != .none
@@ -384,7 +384,7 @@ open class Legend: ComponentBase
 
             neededWidth = maxLineWidth
             neededHeight = labelLineHeight * CGFloat(calculatedLineSizes.count) +
-                yEntrySpace * CGFloat(calculatedLineSizes.count == 0 ? 0 : (calculatedLineSizes.count - 1))
+                yEntrySpace * CGFloat(calculatedLineSizes.isEmpty ? 0 : (calculatedLineSizes.count - 1))
         }
 
         neededWidth += xOffset

Source/Charts/Data/Implementations/Standard/BarChartDataEntry.swift

@@ -89,22 +89,14 @@ open class BarChartDataEntry: ChartDataEntry
         self.data = data
     }
 
-    @objc open func sumBelow(stackIndex :Int) -> Double
+    @objc open func sumBelow(stackIndex: Int) -> Double
     {
-        guard let yVals = _yVals else
+        guard let yVals = _yVals, yVals.indices.contains(stackIndex) else
         {
             return 0
         }
-
-        var remainder: Double = 0.0
-        var index = yVals.count - 1
-
-        while (index > stackIndex && index >= 0)
-        {
-            remainder += yVals[index]
-            index -= 1
-        }
-
+
+        let remainder = yVals[stackIndex...].reduce(into: 0.0) { $0 += $1 }
         return remainder
     }
 

Source/Charts/Data/Implementations/Standard/ChartData.swift

@@ -258,7 +258,7 @@ open class ChartData: NSObject, ExpressibleByArrayLiteral
     /// - Returns: The entry that is highlighted
     @objc open func entry(for highlight: Highlight) -> ChartDataEntry?
     {
-        guard highlight.dataSetIndex < dataSets.count else { return nil }
+        guard highlight.dataSetIndex < dataSets.endIndex else { return nil }
         return self[highlight.dataSetIndex].entryForXValue(highlight.x, closestToY: highlight.y)
     }
 
@@ -277,7 +277,7 @@ open class ChartData: NSObject, ExpressibleByArrayLiteral
     @objc(dataSetAtIndex:)
     open func dataSet(at index: Index) -> Element?
     {
-        guard index >= 0 && index < dataSets.count else { return nil }
+        guard dataSets.indices.contains(index) else { return nil }
         return self[index]
     }
 
@@ -295,7 +295,7 @@ open class ChartData: NSObject, ExpressibleByArrayLiteral
     @objc(addEntry:dataSetIndex:)
     open func appendEntry(_ e: ChartDataEntry, toDataSet dataSetIndex: Index)
     {
-        guard dataSets.count > dataSetIndex && dataSetIndex >= 0 else {
+        guard dataSets.indices.contains(dataSetIndex) else {
             return print("ChartData.addEntry() - Cannot add Entry because dataSetIndex too high or too low.", terminator: "\n")
         }
 
@@ -307,7 +307,7 @@ open class ChartData: NSObject, ExpressibleByArrayLiteral
     /// Removes the given Entry object from the DataSet at the specified index.
     @objc @discardableResult open func removeEntry(_ entry: ChartDataEntry, dataSetIndex: Index) -> Bool
     {
-        guard dataSetIndex < dataSets.count else { return false }
+        guard dataSets.indices.contains(dataSetIndex) else { return false }
 
         // remove the entry from the dataset
         let removed = self[dataSetIndex].removeEntry(entry)
@@ -327,7 +327,7 @@ open class ChartData: NSObject, ExpressibleByArrayLiteral
     @objc @discardableResult open func removeEntry(xValue: Double, dataSetIndex: Index) -> Bool
     {
         guard
-            dataSetIndex < dataSets.count,
+            dataSets.indices.contains(dataSetIndex),
             let entry = self[dataSetIndex].entryForXValue(xValue, closestToY: .nan)
             else { return false }
 

Source/Charts/Data/Implementations/Standard/CombinedChartData.swift

@@ -252,20 +252,8 @@ open class CombinedChartData: BarLineScatterCandleBubbleChartData
     /// - Returns: The entry that is highlighted
     @objc override open func entry(for highlight: Highlight) -> ChartDataEntry?
     {
-        if highlight.dataIndex >= allData.count
-        {
-            return nil
-        }
-
-        let data = dataByIndex(highlight.dataIndex)
-
-        if highlight.dataSetIndex >= data.endIndex
-        {
-            return nil
-        }
-
         // The value of the highlighted entry could be NaN - if we are not interested in highlighting a specific value.
-        return data[highlight.dataSetIndex]
+        getDataSetByHighlight(highlight)?
             .entriesForXValue(highlight.x)
             .first { $0.y == highlight.y || highlight.y.isNaN }
     }
@@ -276,20 +264,21 @@ open class CombinedChartData: BarLineScatterCandleBubbleChartData
     ///   - highlight: current highlight
     /// - Returns: dataset related to highlight
     @objc open func getDataSetByHighlight(_ highlight: Highlight) -> ChartDataSetProtocol!
-    {  
-        if highlight.dataIndex >= allData.count
+    {
+        guard allData.indices.contains(highlight.dataIndex) else
         {
             return nil
         }
-        
+
         let data = dataByIndex(highlight.dataIndex)
-        
-        if highlight.dataSetIndex >= data.endIndex
+
+        guard data.indices.contains(highlight.dataSetIndex) else
         {
             return nil
         }
-
-        return data.dataSets[highlight.dataSetIndex]
+
+        // The value of the highlighted entry could be NaN - if we are not interested in highlighting a specific value.
+        return data[highlight.dataSetIndex]
     }
 
     // MARK: Unsupported Collection Methods

Source/Charts/Data/Implementations/Standard/PieChartData.swift

@@ -69,7 +69,7 @@ open class PieChartData: ChartData
 
     open override func dataSet(forLabel label: String, ignorecase: Bool) -> ChartDataSetProtocol?
     {
-        if dataSets.count == 0 || dataSets[0].label == nil
+        if dataSets.first?.label == nil
         {
             return nil
         }

Source/Charts/Filters/DataApproximator+N.swift

@@ -78,12 +78,12 @@ extension DataApproximator {
         var keep = [Bool](repeating: false, count: points.count)
 
         // first and last always stay
-        keep[0] = true
-        keep[points.count - 1] = true
+        keep[points.startIndex] = true
+        keep[points.endIndex - 1] = true
         var currentStoredPoints = 2
 
         var queue = [LineAlt]()
-        let line = LineAlt(start: 0, end: points.count - 1, points: points)
+        let line = LineAlt(start: points.startIndex, end: points.endIndex - 1, points: points)
         queue.append(line)
 
         repeat {

Source/Charts/Filters/DataApproximator.swift

@@ -27,14 +27,14 @@ open class DataApproximator: NSObject
         var keep = [Bool](repeating: false, count: points.count)
 
         // first and last always stay
-        keep[0] = true
-        keep[points.count - 1] = true
+        keep[points.startIndex] = true
+        keep[points.endIndex - 1] = true
 
         // first and last entry are entry point to recursion
         reduceWithDouglasPeuker(points: points,
                                 tolerance: tolerance,
-                                start: 0,
-                                end: points.count - 1,
+                                start: points.startIndex,
+                                end: points.endIndex - 1,
                                 keep: &keep)
 
         // create a new array with series, only take the kept ones

Source/Charts/Formatters/IndexAxisValueFormatter.swift

@@ -15,22 +15,8 @@ import Foundation
 @objc(ChartIndexAxisValueFormatter)
 open class IndexAxisValueFormatter: NSObject, AxisValueFormatter
 {
-    private var _values: [String] = [String]()
-    private var _valueCount: Int = 0
-
-    @objc public var values: [String]
-    {
-        get
-        {
-            return _values
-        }
-        set
-        {
-            _values = newValue
-            _valueCount = _values.count
-        }
-    }
-
+    @objc public var values: [String] = [String]()
+
     public override init()
     {
         super.init()
@@ -54,6 +40,6 @@ open class IndexAxisValueFormatter: NSObject, AxisValueFormatter
     {
         let index = Int(value.rounded())
         guard values.indices.contains(index), index == Int(value) else { return "" }
-        return _values[index]
+        return values[index]
     }
 }

Source/Charts/Highlight/BarHighlighter.swift

@@ -74,7 +74,7 @@ open class BarHighlighter: ChartHighlighter
 
         guard
             let ranges = entry.ranges,
-            ranges.count > 0
+            !ranges.isEmpty
             else { return nil }
 
         let stackIndex = getClosestStackIndex(ranges: ranges, value: yValue)
@@ -101,7 +101,7 @@ open class BarHighlighter: ChartHighlighter
         if let stackIndex = ranges.firstIndex(where: { $0.contains(value) }) {
             return stackIndex
         } else {
-            let length = max(ranges.count - 1, 0)
+            let length = max(ranges.endIndex - 1, 0)
             return (value > ranges[length].to) ? length : 0
         }
     }

Source/Charts/Highlight/ChartHighlighter.swift

@@ -93,7 +93,7 @@ open class ChartHighlighter : NSObject, Highlighter
         guard let chart = self.chart as? BarLineScatterCandleBubbleChartDataProvider else { return [] }
 
         var entries = set.entriesForXValue(xValue)
-        if entries.count == 0, let closest = set.entryForXValue(xValue, closestToY: .nan, rounding: rounding)
+        if entries.isEmpty, let closest = set.entryForXValue(xValue, closestToY: .nan, rounding: rounding)
         {
             // Try to find closest x-value and take all entries for that x-value
             entries = set.entriesForXValue(closest.x)

Source/Charts/Highlight/CombinedHighlighter.swift

@@ -35,7 +35,7 @@ open class CombinedHighlighter: ChartHighlighter
             let dataObjects = chart.combinedData?.allData
             else { return vals }
 
-        for i in 0..<dataObjects.count
+        for i in dataObjects.indices
         {
             let dataObject = dataObjects[i]
 

Source/Charts/Highlight/HorizontalBarHighlighter.swift

@@ -43,7 +43,7 @@ open class HorizontalBarHighlighter: BarHighlighter
         guard let chart = self.chart as? BarLineScatterCandleBubbleChartDataProvider else { return [] }
 
         var entries = set.entriesForXValue(xValue)
-        if entries.count == 0, let closest = set.entryForXValue(xValue, closestToY: .nan, rounding: rounding)
+        if entries.isEmpty, let closest = set.entryForXValue(xValue, closestToY: .nan, rounding: rounding)
         {
             // Try to find closest x-value and take all entries for that x-value
             entries = set.entriesForXValue(closest.x)

Source/Charts/Renderers/BarChartRenderer.swift

@@ -58,7 +58,7 @@ open class BarChartRenderer: BarLineScatterCandleBubbleRenderer
     {
         guard let barData = dataProvider?.barData else { return _buffers.removeAll() }
 
-        // Matche buffers count to dataset count
+        // Match buffers count to dataset count
         if _buffers.count != barData.count
         {
             while _buffers.count < barData.count
@@ -558,7 +558,7 @@ open class BarChartRenderer: BarLineScatterCandleBubbleRenderer
                             var posY = 0.0
                             var negY = -e.negativeSum
 
-                            for k in 0 ..< vals.count
+                            for k in vals.indices
                             {
                                 let value = vals[k]
                                 var y: Double
@@ -661,7 +661,7 @@ open class BarChartRenderer: BarLineScatterCandleBubbleRenderer
                             }
                         }
 
-                        bufferIndex = vals == nil ? (bufferIndex + 1) : (bufferIndex + vals!.count)
+                        bufferIndex += vals?.count ?? 1
                     }
                 }
             }
@@ -801,7 +801,7 @@ open class BarChartRenderer: BarLineScatterCandleBubbleRenderer
             let labelCount = min(dataSet.colors.count, stackSize)
 
             let stackLabel: String?
-            if (dataSet.stackLabels.count > 0 && labelCount > 0) {
+            if (!dataSet.stackLabels.isEmpty && labelCount > 0) {
                 let labelIndex = idx % labelCount
                 stackLabel = dataSet.stackLabels.indices.contains(labelIndex) ? dataSet.stackLabels[labelIndex] : nil
             } else {

Source/Charts/Renderers/BubbleChartRenderer.swift

@@ -162,7 +162,7 @@ open class BubbleChartRenderer: BarLineScatterCandleBubbleRenderer
 
         var pt = CGPoint()
 
-        for i in 0..<dataSets.count
+        for i in dataSets.indices
         {
             let dataSet = dataSets[i]
 

Source/Charts/Renderers/CandleStickChartRenderer.swift

@@ -281,7 +281,7 @@ open class CandleStickChartRenderer: LineScatterCandleRadarRenderer
 
             var pt = CGPoint()
 
-            for i in 0 ..< dataSets.count
+            for i in dataSets.indices
             {
                 guard let
                     dataSet = dataSets[i] as? BarLineScatterCandleBubbleChartDataSetProtocol,