golang 自动填充字符串，补齐位数

// StrPad
// input string 原字符串
// padLength int 规定补齐后的字符串位数
// padString string 自定义填充字符串
// padType string 填充类型:LEFT(向左填充,自动补齐位数), 默认右侧
func StrPad(input string, padLength int, padString string, padType string) string {

	output := ""
	inputLen := len(input)

	if inputLen >= padLength {
		return input
	}

	padStringLen := len(padString)
	needFillLen := padLength - inputLen

	if diffLen := padStringLen - needFillLen; diffLen > 0 {
		padString = padString[diffLen:]
	}

	for i := 1; i <= needFillLen; i += padStringLen {
		output += padString
	}
	switch padType {
	case "LEFT":
		return output + input
	default:
		return input + output
	}
}

用法：

func main() {
	leftString := StrPad("84792", 10, "0000000000000000000000000", "LEFT")
	rightString := StrPad("1", 5, "0000000000000000", "RIGHT")
	fmt.Println(fmt.Sprintf("%s-%s", leftString, rightString)) //0000084792-10000
}