golang 之字符串截取示例

/golang 字符串截取/

//截取字符串 start 起点下标 length 需要截取的长度

func Substr(str string, start int, length int) string {
	
	rs := []rune(str)
	rl := len(rs)
	end := 0

	if start < 0 {
		start = rl - 1 + start
	}
	end = start + length

	if start > end {
		start, end = end, start
	}

	if start < 0 {
		start = 0
	}
	if start > rl {
		start = rl
	}
	if end < 0 {
		end = 0
	}
	if end > rl {
		end = rl
	}

	return string(rs[start:end])
}

//截取字符串 start 起点下标 end 终点下标(不包括)

func Substr2(str string, start int, end int) string {

	rs := []rune(str)
	length := len(rs)

	if start < 0 || start > length {
		panic("start is wrong")
	}

	if end < 0 || end > length {
		panic("end is wrong")
	}

	return string(rs[start:end])
}


func StrDate()(string)  {

var date string
year:=Substr(time.Now().Format("2006-01-02 15:04"),0,4)
month:= Substr(time.Now().Format("2006-01-02 15:04"),5,2)
year_num,_:=strconv.Atoi(year)
month_num,_:=strconv.Atoi(month)
if(month_num>8||month_num<2){
	year_num++
	date= year+"-"+strconv.Itoa(year_num)+"-1"
}else if(month_num>=2&&month_num<=8){
	year_num--
	date=strconv.Itoa(year_num)+"-"+year+"-2"
}
return date
}


func StrDateLast()(string)  {

var date string
year:=Substr(time.Now().Format("2006-01-02 15:04"),0,4)
month:= Substr(time.Now().Format("2006-01-02 15:04"),5,2)
year_num,_:=strconv.Atoi(year)
month_num,_:=strconv.Atoi(month)
if(month_num>8||month_num<2){
	year_num--
	date=strconv.Itoa(year_num)+"-"+year+"-2"

}else if(month_num>=2&&month_num<=8){
	year_num--
	date=strconv.Itoa(year_num)+"-"+year+"-1"
}
return date

}