ml-go-jff-eps1

main.go

package main

import (
	"bufio"
	"fmt"
	"image/color"
	"log"
	"os"

	"gonum.org/v1/plot"
	"gonum.org/v1/plot/plotter"
	"gonum.org/v1/plot/vg/draw"
)

func main() {
	xys, err := readData("data.txt")
	if err != nil {
		log.Fatalf("could not read data.txt: %v", err)
	}
	// for _, xy := range xys {
	// 	fmt.Println(xy.x, xy.y)
	// }
	p, err := plot.New()
	if err != nil {
		log.Fatalf("could not create plot: %v", err)
	}

	pxys := make(plotter.XYs, len(xys))
	for i, xy := range xys {
		pxys[i].X = xy.x
		pxys[i].Y = xy.y
	}
	scatter, err := plotter.NewScatter(pxys)
	if err != nil {
		log.Fatalf("could not create scatter: %v", err)
	}
	scatter.GlyphStyle.Shape = draw.CrossGlyph{}
	scatter.Color = color.RGBA{R: 255, A: 255}
	p.Add(scatter)

	wt, err := p.WriterTo(512, 512, "png")
	if err != nil {
		log.Fatalf("could not create writer: %v", err)
	}
	imageFile, err := os.Create("out.png")
	if err != nil {
		log.Fatalf("could not create image file: %v", err)
	}
	_, err = wt.WriteTo(imageFile)
	if err != nil {
		log.Fatalf("could not write to out.png: %v", err)
	}

	if err := imageFile.Close(); err != nil {
		log.Fatalf("could not close out.png: %v", err)
	}
}

type xy struct {
	x, y float64
}

func readData(path string) ([]xy, error) {
	file, err := os.Open(path)
	if err != nil {
		return nil, err
	}
	defer file.Close()

	var xys []xy
	scanner := bufio.NewScanner(file)
	for scanner.Scan() {
		var x, y float64
		_, err := fmt.Sscanf(scanner.Text(), "%f,%f", &x, &y)
		if err != nil {
			log.Printf("discarding bad data point %q: %v", scanner.Text(), err)
		}
		xys = append(xys, xy{x, y})
	}
	if err := scanner.Err(); err != nil {
		return nil, fmt.Errorf("could not scan: %v", err)
	}

	return xys, nil
}