Migrated many for loops to their appropriate algorithm

Source/Charts/Charts/ChartViewBase.swift

@@ -207,11 +207,9 @@ open class ChartViewBase: NSUIView, ChartDataProvider, AnimatorDelegate
 
             // calculate how many digits are needed
             setupDefaultFormatter(min: _data.getYMin(), max: _data.getYMax())
-
-            for set in _data.dataSets
-            {
-                if set.needsFormatter || set.valueFormatter === _defaultValueFormatter
-                {
+
+            _data.dataSets.forEach { (set) in
+                if set.needsFormatter || set.valueFormatter === _defaultValueFormatter {
                     set.valueFormatter = _defaultValueFormatter
                 }
             }

Source/Charts/Charts/PieChartView.swift

@@ -228,22 +228,10 @@ open class PieChartView: PieRadarChartViewBase
     /// Checks if the given index is set to be highlighted.
     @objc open func needsHighlight(index: Int) -> Bool
     {
-        // no highlight
-        if !valuesToHighlight()
-        {
-            return false
+        // check if the xvalue for the given dataset needs highlight
+        return _indicesToHighlight.contains {
+            Int($0.x) == index
         }
-
-        for i in 0 ..< _indicesToHighlight.count
-        {
-            // check if the xvalue for the given dataset needs highlight
-            if Int(_indicesToHighlight[i].x) == index
-            {
-                return true
-            }
-        }
-
-        return false
     }
 
     /// calculates the needed angle for a given value
@@ -268,31 +256,19 @@ open class PieChartView: PieRadarChartViewBase
     {
         // take the current angle of the chart into consideration
         let a = (angle - self.rotationAngle).normalizedAngle
-        for i in 0 ..< _absoluteAngles.count
-        {
-            if _absoluteAngles[i] > a
-            {
-                return i
-            }
-        }
-
-        return -1 // return -1 if no index found
+        return absoluteAngles.firstIndex {
+            $0 > a
+        } ?? -1 // return -1 if no index found
     }
 
     /// - returns: The index of the DataSet this x-index belongs to.
     @objc open func dataSetIndexForIndex(_ xValue: Double) -> Int
     {
-        var dataSets = _data?.dataSets ?? []
-
-        for i in 0 ..< dataSets.count
-        {
-            if (dataSets[i].entryForXValue(xValue, closestToY: Double.nan) !== nil)
-            {
-                return i
-            }
-        }
-
-        return -1
+        return _data?
+            .dataSets
+            .firstIndex {
+                $0.entryForXValue(xValue, closestToY: .nan) != nil
+            } ?? -1
     }
 
     /// - returns: An integer array of all the different angles the chart slices

Source/Charts/Charts/PieRadarChartViewBase.swift

@@ -698,27 +698,18 @@ open class PieRadarChartViewBase: ChartViewBase
             return 0.0
         }
 
-        var firstSample = _velocitySamples[0]
-        var lastSample = _velocitySamples[_velocitySamples.count - 1]
-
-        // Look for a sample that's closest to the latest sample, but not the same, so we can deduce the direction
-        var beforeLastSample = firstSample
-        for i in stride(from: (_velocitySamples.count - 1), through: 0, by: -1)
-        {
-            beforeLastSample = _velocitySamples[i]
-            if beforeLastSample.angle != lastSample.angle
-            {
-                break
-            }
-        }
-
+        var firstSample = _velocitySamples.first!
+        var lastSample = _velocitySamples.last!
+
+        // Look for a sample that's closest to the last sample, but not the same, so we can deduce the direction
+        let beforeLastSample = _velocitySamples.reversed()
+            .last {
+                $0.angle == lastSample.angle
+        } ?? firstSample
+
         // Calculate the sampling time
-        var timeDelta = lastSample.time - firstSample.time
-        if timeDelta == 0.0
-        {
-            timeDelta = 0.1
-        }
-
+        let timeDelta = CGFloat(max(lastSample.time - firstSample.time, 0.1))
+
         // Calculate clockwise/ccw by choosing two values that should be closest to each other,
         // so if the angles are two far from each other we know they are inverted "for sure"
         var clockwise = lastSample.angle >= beforeLastSample.angle
@@ -738,7 +729,7 @@ open class PieRadarChartViewBase: ChartViewBase
         }
 
         // The velocity
-        var velocity = abs((lastSample.angle - firstSample.angle) / CGFloat(timeDelta))
+        var velocity = abs((lastSample.angle - firstSample.angle) / timeDelta)
 
         // Direction?
         if !clockwise

Source/Charts/Charts/RadarChartView.swift

@@ -168,20 +168,12 @@ open class RadarChartView: PieRadarChartViewBase
         let sliceAngle = self.sliceAngle
 
         let max = _data?.maxEntryCountSet?.entryCount ?? 0
-
-        var index = 0
-
-        for i in 0..<max
-        {
-            let referenceAngle = sliceAngle * CGFloat(i + 1) - sliceAngle / 2.0
-
-            if referenceAngle > a
-            {
-                index = i
-                break
-            }
-        }
-
+
+        let index = (0..<max).first {
+            let referenceAngle = sliceAngle * CGFloat($0 + 1) - sliceAngle / 2.0
+            return referenceAngle > a
+        } ?? 0
+
         return index
     }
 

Source/Charts/Components/AxisBase.swift

@@ -128,18 +128,12 @@ open class AxisBase: ComponentBase
 
     @objc open func getLongestLabel() -> String
     {
-        var longest = ""
-
-        for i in 0 ..< entries.count
-        {
-            let text = getFormattedLabel(i)
-
-            if longest.count < text.count
-            {
-                longest = text
-            }
+        let longest = entries.indices
+            .reduce("") {
+                let text = getFormattedLabel($1)
+                return $0.count < text.count ? text : $0
         }
-        
+
         return longest
     }
 
@@ -261,13 +255,8 @@ open class AxisBase: ComponentBase
     /// Removes the specified ChartLimitLine from the axis.
     @objc open func removeLimitLine(_ line: ChartLimitLine)
     {
-        for i in 0 ..< _limitLines.count
-        {
-            if _limitLines[i] === line
-            {
-                _limitLines.remove(at: i)
-                return
-            }
+        if let index = _limitLines.firstIndex(where: { $0 === line }) {
+            _limitLines.remove(at: index)
         }
     }
 

Source/Charts/Data/Implementations/ChartBaseDataSet.swift

@@ -245,14 +245,9 @@ open class ChartBaseDataSet: NSObject, IChartDataSet
     /// - parameter alpha: alpha to apply to the set `colors`
     @objc open func setColors(_ colors: [NSUIColor], alpha: CGFloat)
     {
-        var colorsWithAlpha = colors
-
-        for i in 0 ..< colorsWithAlpha.count
-        {
-            colorsWithAlpha[i] = colorsWithAlpha[i] .withAlphaComponent(alpha)
+        self.colors = colors.map {
+            $0.withAlphaComponent(alpha)
         }
-
-        self.colors = colorsWithAlpha
     }
 
     /// Sets colors with a specific alpha value.
@@ -398,15 +393,10 @@ open class ChartBaseDataSet: NSObject, IChartDataSet
     }
 
     open override var debugDescription: String
-    {
-        var desc = description + ":"
-
-        for i in 0 ..< self.entryCount
-        {
-            desc += "\n" + (self.entryForIndex(i)?.description ?? "")
+    {        
+        return (0..<entryCount).reduce(into: description + ":") {
+            $0 += "\n" + (self.entryForIndex($1)?.description ?? "")
         }
-
-        return desc
     }
 
     // MARK: - NSCopying

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

@@ -87,7 +87,6 @@ open class BarChartData: BarLineScatterCandleBubbleChartData
             {
                 fromX += diff
             }
-
         }
 
         notifyDataChanged()

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

@@ -232,16 +232,8 @@ open class BarChartDataEntry: ChartDataEntry
     /// - returns:
     private static func calcSum(values: [Double]?) -> Double
     {
-        guard let values = values
-            else { return 0.0 }
-
-        var sum = 0.0
-
-        for f in values
-        {
-            sum += f
-        }
-
-        return sum
+        return values?.reduce(into: 0.0) {
+            $0 += $1
+        } ?? 0
     }
 }

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

@@ -48,32 +48,17 @@ open class BarChartDataSet: BarLineScatterCandleBubbleChartDataSet, IBarChartDat
     /// stacks. All values belonging to a stack are calculated separately.
     private func calcEntryCountIncludingStacks(entries: [BarChartDataEntry])
     {
-        _entryCountStacks = 0
-
-        for i in 0 ..< entries.count
-        {
-            if let vals = entries[i].yValues
-            {
-                _entryCountStacks += vals.count
-            }
-            else
-            {
-                _entryCountStacks += 1
-            }
+        _entryCountStacks = entries.reduce(into: 0) {
+            $0 += $1.yValues?.count ?? 1
         }
     }
 
     /// calculates the maximum stacksize that occurs in the Entries array of this DataSet
     private func calcStackSize(entries: [BarChartDataEntry])
     {
-        for i in 0 ..< entries.count
-        {
-            if let vals = entries[i].yValues
-            {
-                if vals.count > _stackSize
-                {
-                    _stackSize = vals.count
-                }
+        _stackSize = entries.reduce(into: 1) {
+            if let count = $1.yValues?.count {
+                $0 = count
             }
         }
     }