php - how to detect telephone numbers in a text (and replace them)?

Question

I know it can be done for bad words (checking an array of preset words) but how to detect telephone numbers in a long text? I'm building a website in PHP for a client who needs to avoid people using the description field to put their mobile phone numbers..(see craigslist etc..)

beside he's going to need some moderation but i was wondering if there is a way to block at least the obvious like nnn-nnn-nnnn, not asking to block other weird way of writing like HeiGHT*/four*/nine etc...

Answer 1

Welcome to the world of regular expressions. You're basically going to want to use preg_replace to look for (some pattern) and replace with a string.

Here's something to start you off:

$text = preg_replace('/+?[0-9][0-9()-s+]{4,20}[0-9]/', '[blocked]', $text);

this looks for:

a plus symbol (optional), followed by a number, followed by between 4-20 numbers, brackets, dashes or spaces, followed by a number

and replaces with the string [blocked].

This catches all the obvious combinations I can think of:

012345 123123
+44 1234 123123
+44(0)123 123123
0123456789
Placename 123456 (although this one will leave 'Placename')

however it will also strip out any succession of 6+ numbers, which might not be desirable!