Question

can anybody help me solve this :

i got

$filename= "index 198.php";

i use this and failed

preg_match(" [a-zA-Z0-9]", $filename, $output);

what kind of regex pattern i have to use so the $output array will be consist a number only value.

Answer 1

If you want to extract just the number from the file name you can do:

$filename= "index 198.php";
if(preg_match('#(\d+)#',$filename,$matches))
    echo $matches[1]; // prints 198

It assumes that the file name has just one group of digits. In case if there are more than one group of digits like index 123 abc 456.php only the first group will be matched.

Note:

The regex used is: (\d+)

• \d : short cut for [0-9]. A
  single digit
• \d+ : one or more digits, basically
  a number
• () : to group and remember the match.
  It will be remembered in $matches
  arrray.
• ## : delimiters. preg_ family of
  functions expect the 1st argument
  which is the regex to be inside a
  pair of delimiter. You could have
  used '/(\d+)/' too.