package main
import (
"regexp"
"fmt"
)
func main() {
var re = regexp.MustCompile(`(?m)^(?![_ -])(?:(?![_ -]{2})[\w -]){5,16}(?<![_ -])$`)
var str = `** VALID **
usern
username-is-writ
username is here
username_is_here
** INVALID **
user
username-is-written-here
-username
_username
username
username-
username_
username
username--here
username here
username__here
username- here
username _here`
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/