package main
import (
"regexp"
"fmt"
)
func main() {
var re = regexp.MustCompile(`(?sm)^((?|[1-9](?=.*1\t+(?<x>0+))|[1-9]\d(?=.*2\t+(?<x>0+))|[1-9]\d{2}(?=.*3\t+(?<x>0+))|[1-9]\d{3}(?=.*4\t+(?<x>0+))|[1-9]\d{4}(?=.*5\t+(?<x>0+))|[1-9]\d{5}(?=.*6\t+(?<x>0+))|[1-9]\d{6}(?=.*7\t+(?<x>0+))|[1-9]\d{7}(?=.*8\t+(?<x>0+))))\b`)
var str = `1
12
123
12345678
123456789
1 00000000
2 0000000
3 000000
4 00000
5 0000
6 000
7 00
8 0`
var substitution = "${x}$1"
fmt.Println(re.ReplaceAllString(str, substitution))
}
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Golang, please visit: https://golang.org/pkg/regexp/