[RESOLVED] Regex help - How do I only allow these...

[RonB]

Regex help - How do I only allow these characters: _, ,a-zA-z0-9

I tried using this code, but it didn't work. 🙁

if (!empty($user) && !eregi("[ _a-zA-Z0-9]", $user))
  echo "Bad Username.<br />";

Thank you

Ron

[NogDog]

// negate the character class with "^" to look for invalid characters:
if(!empty($user) && preg_match('/[^\w ]/', $user))
{
   echo "Bad Username.<br />\n";
}

(In preg*() regexes, \w == [a-zA-Z0-9])

[RonB]

Thank you NogDog, that helped a lot! 🙂

[bogu]

Ofc, you can mark this thread RESOLVED. 🙂

[jazz_snob]

RonB, looks like you were trying to allow the space character to be a legal character in your original post? That opens all kinds of bad doors IMHA. \w doesn't include the space character.