Example natural languag date sort

natural-language-date-sort.go

package main

import (
	"fmt"
	"regexp"
	"sort"
	"strconv"
	"time"
)

// Define a regex to capture the day, month, and year
var dateRegex = regexp.MustCompile(`(\d{1,2})\s+([A-Za-z]+)\s+(\d{4})`)

// Mapping month abbreviations to their numeric value
var monthMap = map[string]int{
	"Jan":  1,
	"Feb":  2,
	"Mar":  3,
	"Apr":  4,
	"May":  5,
	"Jun":  6,
	"Jul":  7,
	"Aug":  8,
	"Sep":  9,
	"Sept": 9, // Sept typo example
	"Oct":  10,
	"Nov":  11,
	"Dec":  12,
}

// Convert a string date to time.Time for comparison
func parseDate(dateStr string) (time.Time, error) {
	matches := dateRegex.FindStringSubmatch(dateStr)
	if matches == nil {
		return time.Time{}, fmt.Errorf("invalid date format")
	}

	day, _ := strconv.Atoi(matches[1])
	month, ok := monthMap[matches[2]]
	if !ok {
		return time.Time{}, fmt.Errorf("invalid month format")
	}
	year, _ := strconv.Atoi(matches[3])

	return time.Date(year, time.Month(month), day, 0, 0, 0, 0, time.UTC), nil
}

// Sort a list of dates in natural order
func sortDates(dates []string) ([]string, error) {
	sort.Slice(dates, func(i, j int) bool {
		dateI, err := parseDate(dates[i])
		if err != nil {
			return false
		}
		dateJ, err := parseDate(dates[j])
		if err != nil {
			return true
		}
		return dateI.Before(dateJ)
	})

	return dates, nil
}

func main() {
	dates := []string{
		"16 Sep 2023",
		"10 Sep 2023",
		"01 Jan 1970",
		"13 Sep 2023",
		"15 Sept 2023",
		"12 Mar 1990",
		"14 Sep 2023",
	}

	sortedDates, err := sortDates(dates)
	if err != nil {
		fmt.Println(err)
		return
	}

	for _, date := range sortedDates {
		fmt.Println(date)
	}
}