推荐订阅源

package main

import (
    "fmt"
)

func main() {
    a := 1
    fmt.Println(a)
    //前置补0
    fmt.Printf("%03d", a)
    fmt.Println("")
    fmt.Printf("%0*d", 3, a)
}

[ `run` | done: 1.581527ms ]
  1
  001
  001