package main
import (
"regexp"
"fmt"
)
func main() {
var re = regexp.MustCompile(`(?m)^(?:[a-zA-Z0-9]+[._]?[a-zA-Z0-9]+)+$`)
var str = `username
user_name
user.name
user.name_123
username$$$
_username
username_
user_.name
user._name
user__name
user..name
`
for i, match := range re.FindAllString(str, -1) {
fmt.Println(match, "found at index", i)
}
}
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/