package main
import (
"regexp"
"fmt"
)
func main() {
var re = regexp.MustCompile(`(?m)^[a-zA-Z][a-zA-Z0-9_]{3,24}$(?<!_)`)
var str = `The username is between 4 and 25 characters.
It must start with a letter.
It can only contain letters, numbers, and the underscore character.
It cannot end with an underscore character.`
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/