is_numeric & White Space

[adam_smith123]

How do I validate a string to make sure it only contains numerals and allow spaces?

I want to make sure that there are numbers entered, and if so, spaces may be used.

I have used is_numeric but this does not allow spaces.

Thanks

[cahva]

example:

$str='1d23123 123213';
if (is_numeric(str_replace(' ','',$str)))
        echo 'ok';
else
        echo 'false';

[LordShryku]

Can also just use a regular expression.

if(ereg('[^0-9 ]', $string))
   echo 'Invalid!';
else
   echo 'Valid!';

[Weedpacket]

Don't even need regular expressions.

if(strspn($string,'0123456789 ')==strlen($string))
//valid

if(ltrim($string, '0..9 ')=='')
//valid

Cuddle up with the manual, it's good for a giggle.