regular expressions - simple question

[syn]

Hello.

I am trying to valid a string from a form post. anyways, the string can only start with a-z and 0-9 but can contain a-z 0-9 -_ but i can't get it to work for the life of me 😕 .

this is what i think it should look like but its not working.

"^{[a-z0-9][a-z0-9_-]"}

in the code:

if (eregi("^{[a-z0-9][a-z0-9_-]",$MyVar))}
{
echo "string failed check";
}

thanks.

[rincewind456]

This maybe

^[a-zA-Z0-9._-]+$

[Weedpacket]

if (!eregi("^[a-z0-9][a-z0-9_\-]*",$MyVar))

And have a look at upgrading to preg_match(); a little bird told me that ereg() and eregi() will probably be going away in PHP6....

[syn]

It works great, but as soon as your add a space it fails.

IE,

asdfasdf -> good
dfjd_test -> good
_kdjfjkdf -> bad
dkjfkdj dfdf -> good
dkjfkdf %^& -> good

any sugestions? thanks for the prev. input tho!

CODE:
<?php
if (isset($POST['test']))
{
if (!eregi("(^{[a-z0-9])([a-z0-9}-]*)",$POST['test']))
{
echo "<PRE>failed [" . $POST['test'] . "]";
}
else
{
echo "<PRE> passed [" . $_POST['test'] . "]";
}
}
?>
<FORM ACTION=email.php METHOD=POST>
<INPUT TYPE=TEXT NAME=test SIZE=30>
<INPUT TYPE=submit value=go>
</FORM>

[Swardh]

preg_match('/^[a-z0-9][_\-\%\^& ]*/i',$_POST['test'])

[Weedpacket]

if (!eregi("^[a-z0-9][a-z0-9_\-]*$",$MyVar)) 

then. I can't be expected to do all my own debugging, can I?