fix

series/csv.go

@@ -0,0 +1,114 @@
+package series
+
+import (
+	"encoding/csv"
+	"fmt"
+	"os"
+	"slices"
+	"strconv"
+	"strings"
+)
+
+type CSVData struct {
+	Columns []string
+	Rows    [][]string
+	index   map[string]int
+}
+
+func ReadCSV(path string) (*CSVData, error) {
+	file, err := os.Open(path)
+	if err != nil {
+		return nil, err
+	}
+	defer file.Close()
+
+	records, err := csv.NewReader(file).ReadAll()
+	if err != nil {
+		return nil, err
+	}
+	if len(records) == 0 {
+		return &CSVData{Columns: []string{}, Rows: [][]string{}, index: map[string]int{}}, nil
+	}
+
+	data := &CSVData{
+		Columns: records[0],
+		Rows:    records[1:],
+		index:   make(map[string]int, len(records[0])),
+	}
+	for i, column := range data.Columns {
+		data.index[strings.ToLower(strings.TrimSpace(column))] = i
+	}
+	return data, nil
+}
+
+func (d *CSVData) Index(name string) (int, error) {
+	idx, ok := d.index[strings.ToLower(name)]
+	if !ok {
+		return -1, fmt.Errorf("missing column %q", name)
+	}
+	return idx, nil
+}
+
+func (d *CSVData) NumericColumns(names ...string) ([][]float64, error) {
+	indices := make([]int, len(names))
+	for i, name := range names {
+		idx, err := d.Index(name)
+		if err != nil {
+			return nil, err
+		}
+		indices[i] = idx
+	}
+
+	values := make([][]float64, len(names))
+	for i := range values {
+		values[i] = make([]float64, 0, len(d.Rows))
+	}
+
+	maxIndex := MaxInt(indices...)
+	for _, row := range d.Rows {
+		if len(row) <= maxIndex {
+			continue
+		}
+
+		parsed := make([]float64, len(indices))
+		valid := true
+		for i, idx := range indices {
+			value, err := ParseFloat(row[idx])
+			if err != nil {
+				valid = false
+				break
+			}
+			parsed[i] = value
+		}
+		if !valid {
+			continue
+		}
+
+		for i, value := range parsed {
+			values[i] = append(values[i], value)
+		}
+	}
+
+	return values, nil
+}
+
+func ParseFloat(value string) (float64, error) {
+	return strconv.ParseFloat(strings.TrimSpace(value), 64)
+}
+
+func MaxInt(values ...int) int {
+	max := 0
+	for _, value := range values {
+		if value > max {
+			max = value
+		}
+	}
+	return max
+}
+
+func MaxLastHalf(values []float64) float64 {
+	if len(values) == 0 {
+		return 0
+	}
+	return slices.Max(values[len(values)/2:])
+}