regex - Regular Expression for matching a phone number

Question

I need a regular expression to match phone numbers. I just want to know if the number is probably a phone number and it could be any phone format, US or international. So I developed a strategy to determine if it matches.

I want it to accept the following characters: 0-9 as well as ,.()- and optionally start with a + (for international numbers). The string should not match if it has any other characters.

I tried this:

/+?[0-9/.()-]/

But it matches phone numbers that have + in the middle of the number. And it matches numbers that contain alpha chars (I don't want that).

Lastly, I want to set the minimum length to 9 characters.

Any thoughts?

Thanks for any help, I'm obviously not too swift on RegEx stuff :)

Answer 1

Well, you're pretty close. Try this:

^+?[0-9/.()-]{9,}$

Without the start and end anchors you allow partial matching, so it can match +123 from the string :-)+123.

If you want a minimum of 9 digits, rather than any characters (so ---.../// isn't valid), you can use:

^+?[/.()-]*([0-9][/.()-]*){9,}$

or, using a lookahead - before matching the string for [0-9/.()-]* the regex engine is looking for (D*d){9}, which is a of 9 digits, each digit possibly preceded by other characters (which we will validate later).

^+?(?=(D*d){9})[0-9/.()-]*$