Re: Regular expression problems
| From: | Simon Garner | Date: | Mon, 26 Feb 2001 03:45:42 +0000 |
| Subject: | Re: Regular expression problems | ||
| References: | 1 | Groups: | php.general |
| Request: | Send a blank email to php-general+get-41641@lists.php.net to get a copy of this message | ||
From: "Dan Watt" <danwatt@mediaone.net>
> Im trying to build a user login system, and when there is a new user, I
need
> to validate that they are usign using word characters ([0-9A-Za-z_] or
> \w)... I have TRIED MANY different regular expressions to test this, but
> none work. This seems so simple but I am missing something. I need a
> expression that returs true ONLY if ALL the characters match \w .... Any
> help would be appreciated.
>
>
<?php
$username = "johnny";
if (!eregi("[^A-Z0-9_-]", $username))
{
echo "username OK";
}
else
{
echo "bad username!";
}
?>
Assuming you only want letters, numbers, underscores or hyphens. If you
really want \w you would need to use preg instead of ereg, and then you need
PCRE support in PHP. Or you could use ereg's character classes, I think the
pattern would look like: "[^[:alphanum:]]". However you are probably better
off using an explicit set of characters as I have shown, so that it is
obvious what is and is not allowed.
Cheers
Simon Garner