Convert (b,mb,gb,tb,pb) Memory data to kb using regex in Golang

main.go

package main

import (
	"fmt"
	"regexp"
	"strconv"
	"strings"
)

func main() {
	sizes := []string{"12pb", "12p", "12tb", "12t", "12gb", "12g", "12mb", "12m", "12kb", "12k", "12222b", "12", "12PB", "12P", "12TB", "12T", "12GB", "12G", "12MB", "12M", "12KB", "12K", "12222B", "12"}
	// pb = petabytes
	// p = petabytes
	// tb = terabytes
	// t = terabytes
	// gb = gigabytes
	// g = gigabytes
	// mb = megabytes
	// m = megabytes
	// kb = kilobytes
	// k = kilobytes
	// b = bytes

	for _, size := range sizes {
		regKb, err := regexToKB(size)
		if err != nil {
			fmt.Printf("error converting %s to KB: %v\n", size, err)
		} else {
			fmt.Printf("regex- %s = %d KB\n", size, regKb)
		}
	}
}

func regexToKB(size string) (int64, error) {
	regex := regexp.MustCompile(`^(\d+)([bkmgtp]?b?)$`)
	match := regex.FindStringSubmatch(strings.ToLower(size))
	if match == nil {
		return 0, fmt.Errorf("invalid size format: %s", size)
	}

	num, err := strconv.ParseInt(match[1], 10, 64)
	if err != nil {
		return 0, fmt.Errorf("invalid size format: %s", size)
	}

	var kb int64
	switch strings.TrimSuffix(match[2], "b") {
	case "":
		return num, nil
	case "k":
		kb = 1024
	case "m":
		kb = 1024 * 1024
	case "g":
		kb = 1024 * 1024 * 1024
	case "t":
		kb = 1024 * 1024 * 1024 * 1024
	case "p":
		kb = 1024 * 1024 * 1024 * 1024 * 1024
	default:
		return 0, fmt.Errorf("invalid size format: %s", size)
	}

	return num * kb / 1024, nil
}

regex := regexp.MustCompile(`^(\d+)([bkmgtp]?b?)$`)

^ matches the start of the string.
(\d+) matches one or more digits and captures them in a group.
([bkmgtp]?b?) matches a letter
$ matches the end of the string.

I hope this helps you!