pie chart/plot in swift

Don't be depressed. You just have to add a more specific question to get more help. For example, if you start from scratch and try to integrate a plots package from Github, you have to say what package, how did you try to integrate it, what errors are you getting etc.

However, drawing a simple pie chart is pretty easy with CoreGraphics functionality. Here is a little gift from my code, this draws progress value as a simple black and white pie chart. It only has 2 sections, but you can generalize from it

@IBDesignable class ProgressPieIcon: UIView {
    @IBInspectable var progress : Double =  0.0 {
        didSet {
            self.setNeedsDisplay()
        }
    }

    required init(coder aDecoder: NSCoder) {
        super.init(coder:aDecoder)
        self.contentMode = .Redraw
    }

    override init(frame: CGRect) {
        super.init(frame: frame)
        self.backgroundColor = UIColor.clearColor()
        self.contentMode = .Redraw
    }

    override func drawRect(rect: CGRect) {
        let color = UIColor.blackColor().CGColor
        let lineWidth : CGFloat = 2.0

        // Calculate box with insets
        let margin: CGFloat = lineWidth
        let box0 = CGRectInset(self.bounds, margin, margin)
        let side : CGFloat = min(box0.width, box0.height)
        let box = CGRectMake((self.bounds.width-side)/2, (self.bounds.height-side)/2,side,side)


        let ctx = UIGraphicsGetCurrentContext()

        // Draw outline
        CGContextBeginPath(ctx)
        CGContextSetStrokeColorWithColor(ctx, color)
        CGContextSetLineWidth(ctx, lineWidth)
        CGContextAddEllipseInRect(ctx, box)
        CGContextClosePath(ctx)
        CGContextStrokePath(ctx)

        // Draw arc
        let delta : CGFloat = -CGFloat(M_PI_2)
        let radius : CGFloat = min(box.width, box.height)/2.0

        func prog_to_rad(p: Double) -> CGFloat {
            let rad = CGFloat(p * 2 * M_PI)
            return rad + delta
        }

        func draw_arc(s: CGFloat, e: CGFloat, color: CGColor) {
            CGContextBeginPath(ctx)
            CGContextMoveToPoint(ctx, box.midX, box.midY)
            CGContextSetFillColorWithColor(ctx, color)

            CGContextAddArc(
                ctx,
                box.midX,
                box.midY,
                radius-lineWidth/2,
                s,
                e,
                0)

            CGContextClosePath(ctx)
            CGContextFillPath(ctx)
        }

        if progress > 0 {
            let s = prog_to_rad(0)
            let e = prog_to_rad(min(1.0, progress))
            draw_arc(s, e, color)
        }
   }