regular expression

keith2004

ive been searching and reading tutorials for days now and i cant figure it out🙁

i have an imput feild that visitors to my site can enter information into...

because i will be using the values inside html tags i have to be careful what i allow them to enter.

can somebody tell me what the regular expression is (PCRE-Style) so that only letters or numbers can be entered or leave the feild blank..

ive nearly got it working using

^[A-Z0-9?]^

but if they leave the feild empty they get an invalid response:mad:

if i add * or ? it works ok when they leave the feild blank but it also allows them to enter the dreaded dot

any ideas anyone

this is giving me a right headache😕

AstroTeg

If the field is blank, test it BEFORE you do your regular expression work. If its blank, there's no checking to do anyways.

keith2004

ordinarily i would but...

im using a phpbb module
(custom profiles mod)

which gives the ability to add and delete feilds in the profile...

it only gives the facilty to enter regular expression(pcre style) to avaluate the text feild

:mad:

swr

Use this:

preg_match('/^{[a-z0-9]*$/i',} $string);

The is important, as it means "zero or more of the previous character". Without the , it must match exactly one character, which is why you were having problems.

Also, ^ is beginning of string, $ is end of string (you had ^ on the beginning and end).

keith2004


preg_match('/^[a-z0-9]*$/i', $string);

gives me


You have an error in your regular expression syntax:

Delimiter must not be alphanumeric or backslash

😕

swr

Works fine here. Are you sure you didn't garble your copy+paste?

cmose

I had a problem with a regular expression in an earlier thread and someone suggested I download "the regex coach" it's free ware and damned helpful with regular expressions, just remember to add the / and / at beginning and end of regex for php (at least in the ones I've used/tested those are needed).

can't help with your specific problem although you could checkout www.regexlib.com for one that's already been made/tested (i think I grabbed something similar from regexlib.com)

keith2004

found it😃

/^[0-9a-zA-Z]{0,9}$/

thanks people😉