check if a string contains a letter followed by a number

[ahmed24]

hi i have a variable called $username like this:

$username = $_POST['username'];

i want to be able to check to see if the value for $username starts with the letter p (not case sensative) and is followed by a numeric set of values. If so echo something else echo something else

can anyone tell me how i can achieve this?

thanks

[janharders]

Just use [url=www.php.net/preg_match]preg_match[/url] to check for ^p\d+$ or ^p(\d+)$ if you want to work on the numeric part.

[ahmed24]

i've managed to do this:

if (!preg_match('/[[:^digit:]]/', $username)) { }

but this only detects if it is a number, how can i determine if it also begins with a letter p ?

[janharders]

As I said, use ^p\d+$ as the regexp (that's [[:^digit:]] in your example) to check for that. the ^ matches at the beginning of the string, and $ at the end, so that'll let p123 through, but not p123a or ap123.

[ahmed24]

thats great, works perfectly now.

thanks