Stripping everything but alphanumeric chars from a string in PHP

I'd like a regexp or other string which can replace everything except alphanumeric chars (a-z and 0-9) from a string. All things such as ,@#$(@*810 should be stripped. Any ideas?

Edit: I now need this to strip everything but allow dots, so everything but a-z, 1-9, .. Ideas?

From stackoverflow

• /[^a-z0-9.]/
  

  should do the trick

  Click Upvote : How can i change that to allow only dots (i.e .)?

  Gumbo : @ Click Upvote: `[^.]`

  Click Upvote : Full reg exp please? I don't know the syntax

• Try:

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

  /i stands for case insensitivity (if you need it, of course).

• $string = preg_replace("/[^a-z0-9.]+/i", "", $string);
  

  Matches one or more characters not a-z 0-9 [case-insensitive], or "." and replaces with ""

  Click Upvote : How can i change that to allow only dots (i.e .)?

  gnarf : Adjusted to also include "."

  Gumbo : You don’t need to escape the dot inside the character set.

  gnarf : @gumbo - thanks learned something myself from this one :)

• I like using [^[:alnum:]] for this, less room for error.

  preg_replace('/[^[:alnum:]]/', '', "(ABC)-[123]"); // returns 'ABC123'