regex phone validator ^\+?(\d+)(-(\d+)|( \d+)+)?$

Question

I need a phone validator with the following conditions:

In Use the following regex: ^\+?(\d+)(-(\d+)|( \d+)+)?$

It works but it counts "+" and "-" too.

I can write for ex +123-45678

10 chars but only 8 numbers.

There should always be at least 10 numbers

Could we please see your [mcve] that you have problems with? — kayess, May 13 '16 at 14:19
Possible duplicate of [A comprehensive regex for phone number validation](http://stackoverflow.com/questions/123559/a-comprehensive-regex-for-phone-number-validation) — Kevin Burdett, May 13 '16 at 14:23
My comment above was asking for the specific c# code, probably Q just needs and [edit]. — kayess, May 13 '16 at 14:34
`^(?=(?:\D*\d){10})\+?(\d+)(-\d+|( \d+)+)?$` - here, `(?=(?:\D*\d){10})` will require the string to have at least 10 digits. — Wiktor Stribiżew, May 13 '16 at 14:52

Tom Lord · Answer 1 · 2016-05-13T14:35:42.413

1

Let's take this one part at a time:

You've achieved this already, with:

^\+?

You can achieve this with a lookahead:

^(?=[^-]*-?[^-]*$)

I presume that it should also contain ONLY numbers (and maybe a hyphen)? Again, using a lookahead:

^(?=(\d-?){10})

Putting it all together:

^\+?(?=[^-]*-?[^-]*$)(?=(\d-?){10})

This regex would be a lot simpler if the validation rules were less vague. It really depends on what your intended use is.

edited May 13 '16 at 14:35

answered May 13 '16 at 14:28

Tom Lord

What's your point? Your example was supposed to match, and it matches? – Tom Lord May 13 '16 at 14:31
Ok see [v2](https://regex101.com/r/qK1uM0/2). it matches but it's not supposed to match – Thomas Ayoub May 13 '16 at 14:32
Ahh yeah, fine. OP didn't actually specify that the phone numbers could contain ONLY digits - although that seems sensible. I'll provide the "Improved" variation too. – Tom Lord May 13 '16 at 14:34
and no letters :-| – Ivaapr May 13 '16 at 14:34
Done. All I needed was to change `(\d.*)` to `(\d-?)` – Tom Lord May 13 '16 at 14:38
Don't you think that is overly complex for a relatively easy requirement to just check a digit count? It can be done with just 1 lookahead. – Wiktor Stribiżew May 13 '16 at 14:43
@WiktorStribiżew I suppose you could simplify it slightly to: `^\+?(?=[^-]*-?[^-]*$)[\d-]{10,}$`, but the improvement isn't massive :/ – Tom Lord May 13 '16 at 14:56
Yes, but `(?=[^-]*-?[^-]*$)` prevents such a string from matching :) https://regex101.com/r/qK1uM0/4 – Tom Lord May 13 '16 at 15:03
^\+?(?=[^-]*-?[^-]*$)(?=(\d-?){10}) well done! But it works med hyphen at the end – Ivaapr May 13 '16 at 15:10
@Ivaapr At a certain point, when the pattern matching gets too crazy, it's probably worth considering *not* doing this in one big regex ;) However, you could achieve this by simply changing the pattern to: `^\+?(?=[^-]*-?[^-]+$)(?=(\d-?){10})` (I just replaced a `*` with `+`). – Tom Lord May 13 '16 at 15:14

1 Answers1