Using go-chart to generate a graph based on the PRO Prisundersökning data converted using https://gist.github.com/peterhellberg/ceed862a83c29a80b5bbd4631c24fb27

pro-prisundersokning-graph.go

package main

import (
	"encoding/json"
	"fmt"
	"os"
	"strings"

	_ "embed"

	"github.com/wcharczuk/go-chart/v2"
	"github.com/wcharczuk/go-chart/v2/drawing"
)

var (
	orange = drawing.ColorFromHex("FF6600")
	blue   = drawing.ColorFromHex("0099FF")
	gray   = drawing.ColorFromHex("363636")
)

func main() {
	var butiker []butik

	if err := json.Unmarshal(data, &butiker); err != nil {
		panic(err)
	}

	totals := make([]float64, len(butiker))

	var combinedTotal float64

	for i, butik := range butiker {
		totals[i] = butik.Total
		combinedTotal += butik.Total
	}

	averageTotal := combinedTotal / float64(len(totals))

	zero := chart.GridLine{
		Value: averageTotal,
		Style: chart.Style{
			StrokeWidth:     15,
			StrokeColor:     orange.WithAlpha(30),
			StrokeDashArray: []float64{20, 20},
		},
	}

	S, N := 0, 36

	for n := S; n < N; n++ {
		var varorNamn string

		priser := make([]float64, len(butiker))

		for i, butik := range butiker {
			priser[i] = butik.Varor[n].Pris
			varorNamn = butik.Varor[n].Namn
		}

		mainSeries := chart.ContinuousSeries{
			YAxis: chart.YAxisSecondary,
			Style: chart.Style{
				StrokeColor: orange.WithAlpha(80),
				StrokeWidth: 32,
				DotColor:    orange,
				DotWidth:    6,
			},
			XValues: chart.LinearRange(1, float64(len(totals))),
			YValues: chart.ValueSequence(totals...).Values(),
		}

		priserSeries := chart.ContinuousSeries{
			Style: chart.Style{
				StrokeColor: blue.WithAlpha(100),
				StrokeWidth: 3,
				DotColor:    blue.WithAlpha(130),
				DotWidth:    9,
			},
			XValues: chart.LinearRange(1, float64(len(totals))),
			YValues: chart.ValueSequence(priser...).Values(),
		}

		graph := chart.Chart{
			Title: "Hela matkassens pris jämfört med " + varorNamn,
			TitleStyle: chart.Style{
				FontSize:  20,
				FontColor: gray,
			},
			DPI:    216,
			Width:  3072,
			Height: 1536,
			XAxis: chart.XAxis{
				Style: chart.Style{
					Hidden: true,
				},
			},
			YAxisSecondary: chart.YAxis{
				Zero: zero,
				Name: "Hela matkassen",
				NameStyle: chart.Style{
					FontSize:  -16,
					FontColor: orange,
				},
				Style: chart.Style{
					FontSize:    14,
					StrokeWidth: 4,
					StrokeColor: orange,
					FontColor:   orange,
				},
				ValueFormatter: krFormatter,
			},
			YAxis: chart.YAxis{
				Name: varorNamn,
				NameStyle: chart.Style{
					FontSize:  16,
					FontColor: blue,
				},
				Style: chart.Style{
					FontSize:    14,
					StrokeWidth: 4,
					StrokeColor: blue,
					FontColor:   blue,
				},
				ValueFormatter: krFormatter,
			},
			Background: chart.Style{
				Padding: chart.NewBox(80, 60, 20, 20),
			},
			Series: []chart.Series{
				priserSeries,
				mainSeries,
			},
		}

		fn := strings.ToLower(
			fmt.Sprintf("pro-prisundersokning-total-vs-%s.png",
				strings.ReplaceAll(varorNamn, " ", "-"),
			),
		)

		f, err := os.Create(fn)
		if err != nil {
			panic(err)
		}
		defer f.Close()

		if err := graph.Render(chart.PNG, f); err != nil {
			panic(err)
		}
	}
}

func krFormatter(v interface{}) string {
	return chart.FloatValueFormatterWithFormat(v, " %.0f kr")
}

//go:embed data.json
var data []byte

type butik struct {
	Butiksnamn string  `json:"butiksnamn"`
	Distrikt   string  `json:"distrikt"`
	Typ        string  `json:"typ"`
	AntalVaror int     `json:"antal_varor"`
	Total      float64 `json:"total"`
	Varor      []vara  `json:"varor"`
}

type vara struct {
	Namn string  `json:"namn"`
	Pris float64 `json:"pris"`
}

Changes from 2022 to 2023 for "Långkornigt ris"

HTML table for 2022 and 2023 images

package main

import (
	"fmt"
	"log"
	"net/http"
	"os"
	"slices"
	"text/template"
)

func main() {
	images22 := yearImages("./2022/")
	images23 := yearImages("./2023/")

	var products []Product

	for _, name := range imageUnion(images22, images23) {
		products = append(products, Product{
			Name:   name,
			In2022: in(name, images22),
			In2023: in(name, images23),
		})
	}

	fmt.Println(len(products), products)

	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
		t.Execute(w, products)
	})

	images := http.FileServer(http.Dir("."))
	http.Handle("/images/", http.StripPrefix("/images/", images))

	log.Fatal(http.ListenAndServe(":9876", nil))
}

func in(name string, images []string) bool {
	for _, n := range images {
		if name == n {
			return true
		}
	}

	return false
}

type Product struct {
	Name   string
	In2022 bool
	In2023 bool
}

func imageUnion(names ...[]string) []string {
	union := slices.Concat(names...)

	slices.Sort(union)

	union = slices.Compact(union)

	return union
}

func yearImages(dir string) []string {
	var images []string

	files, err := os.ReadDir(dir)
	if err != nil {
		return nil
	}

	for _, f := range files {
		images = append(images, f.Name())
	}

	return images
}

var t = template.Must(template.New("").Parse(`<!doctype html>
<html lang="en" data-theme="light">
	<head>
		<meta charset="utf-8">
		<meta name="viewport" content="width=device-width, initial-scale=1">
		<meta name="apple-mobile-web-app-capable" content="yes">
		<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/@picocss/pico@next/css/pico.fluid.classless.min.css">
		<title>2022 vs 2023</title>
	</head>
	<body>
		<main>
			<article>
				<header>
					<h1><a href="/" style="text-decoration: none; color: #2d3138">PRO Prisundersökning 📝</a></h1>
				</header>
				<table>
<tr><th><h3>2022</h3></th><th><h3>2023</h3></th></tr>
				{{ range . -}}
					<tr>
						<td>
							{{if .In2022 }}<img src="/images/2022/{{.Name}}" />{{else}}{{end}}
						</td>
						<td>
							{{if .In2023 }}<img src="/images/2023/{{.Name}}" />{{else}}{{end}}
						</td>
					</tr>
				{{ end }}
				</table>
			</article>
		</main>
	</body>
</html>`))