golang 截取字符串

package main

import (
	"fmt"
)

func ttrim(dat []byte) []byte {
	flag := false
	start := 0
	end := 0
	for i, v := range dat {
		if (v >= 0 && v <= 9) || (v >= '0' && v <= '9') || (v >= 'a' && v <= 'z') || (v >= 'A' && v <= 'Z') {
			if flag == false {
				start = i
				end = i
				flag = true
			} else {
				end = i
			}
		} else {
			if flag == true {
				fmt.Println("start ,end =", start, end)
				end = i
				break
			}
		}
	}

	return dat[start:end]
}

func main() {
	fmt.Println("vim-go")
	str := "*?>?,.,.,.?>>a123kjdslrd90jcd09er0jejj9*,=_---->>>....,l+"
	ss := ttrim([]byte(str))
	fmt.Println(str)
	fmt.Println(string(ss))
}