Help with Regex using preg_match

Question

Hi,

Recently i've switched to PHP 5.3+ and after that migration i learned that the eregi() function has been depreciated, its the function i mostly used for my regex needs.

But now i had to switch to preg_match() function, i am having trouble validating a certain condition.

Hello World

I want the preg_match to validate the above "hello world" string, the string contains whitespace in it.

But i want it to validate even if there is no whitespace "helloWorld" or just "hello".

What i'm trying to do is that in my script i have a text-field for the category title, i want it to accept spaces in it and no other special characters (such as ._-+*,).

I have made it to work but i'm not sure if thats the right way which i'm using.

preg_match('/^[a-zA-Z0-9\s]*$/', $cat_name);'

Any help would be appreciated.

Answer 1

Yes, that is the correct way. You can also use an insensitive-case modifier instead of a-zA-Z:

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

One thing that you might want to consider is that your regular expression currently accepts the empty string. If you want to ensure that there is at least one character then use + instead of *.

Answer 2

Note that \s also allows other space characters like tabulator or newline.

Answer 3

Looks OK, but will accept empty string, so you can change * to + Remember that this regex will propably no accept language-specified UTF-8 chars.

See that comment in manual: http://www.php.net/manual/en/function.preg-match.php#95828

Also note, that some specific charaters are very often used in titles, like " and maybe it would better to allow it.

Answer 4

Should work, but you can replace the \s with a normal space " ", so it only matches spaces instead of other whitespace chars (like tabs). Also replace the * with + so it won't take empty strings.

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