Stripping a phone number of its parenthesis, spaces, and hyphens in PHP?

Question

I have a phone number stored in $phone, it looks like this: (555) 555-5555. I want it to look like this: 5555555555. How do I take the string and strip it of hyphens, spaces, and parenthesis?

Answer 1

With a regexp. Specifically, use the preg_replace function:

$phone = preg_replace('/\D+/', '', $phone);