Regex for phone number with specific area code and format

Question

I'm trying to create a regular expression that would validate a specific phone number with an 868 area code and particular format h thus I want these

8680000000

(868) 000 0000

868-000-0000

868 000-0000

to pass validation but these

8880000000

767-000-0000

868-0000000

(868)0000000

to fail validation.

So far I got:

^((\(){0,1}(868){1}(\)){0,1})+:?((((\ |\-)(\d{3})(\ |\-)):?\d{4})+|(\d{4,7}))

But

(868)0000000 

is validating

Answer 1

I genuinely do not understand why everyone need to validate a phone number with strict spacing, bracketing, hyphenation, and god-knows-what-else requirements.

Strip out all unnecessary characters, validate what needs validating, move on with life.

$phone = '(868) 555-1234'; // or 868 555.1234 or +868x55-5-123-4 etc
$phone = preg_replace('/[^0-9]/', '', $phone); // 8685551234
if( substring($phone, 0, 3) == '868' ) {
  // great success
}

Bonus round. Format your data for hu-man display:

$phone_display = sprintf('(%s) %s-%s',
  substring($phone,0,3),
  substring($phone,3,3),
  substring($phone,6,4));

Answer 2

Actually this is somewhat hard-coded because you are having some specific requirements like validating 868-000-0000 but not 868-0000000 .

Regex is:

(^\(868\)\ \d{3}\ \d{4})|(^868\d{7})|(^868\-\d{3}\-\d{4})|(^868\ \d{3}\-\d{4})

DEMO

Answer 3

Such regex

^(\(?868\)?(\s*|-)\d{3}(\s|-)\d{4}|868\d{7})$

Validate these

8680000000
(868) 000 0000
868-000-0000
868 000-0000

Not validate

8880000000
767-000-0000
868-0000000
(868)0000000

match[1] contains number

DEMO and explanation of the regex

Answer 4

You can do this with some conditionals

 # ^(\()?868(?(1)\)[ ]\d{3}[ ]\d{4}|(?:(?:(-)|([ ])|)\d{3}(?(2)\2|(?(3)[ -]))\d{4}))$

 ^                             # BOS
 ( \( )?                       # (1), Form (xxx) xxx xxxx
 868                           # 868 Area Code
 (?(1)                         # Need Form 1 ?
      \)
      [ ] \d{3} [ ] \d{4} 
   |                              # else
      (?:
           (?:
                ( - )                         # (2), Form xxx-xxx-xxxx
             |  ( [ ] )                       # (3), Form xxx xxx[ -]xxxx
             |                              # Form xxxxxxxxxx
           )
           \d{3}      
           (?(2)                         # Need form 2 ?
                \2 
             |                              # else
                (?(3) [ -] )                  # Need form 3 ?
           )
           \d{4}      
      )
 )
 $                             # EOS

Passed:

8680000000
(868) 000 0000
868-000-0000
868 000-0000

Failed:

8880000000
767-000-0000
868-0000000
(868)0000000

Answer 5

You could write one regular expression that matches all the formats, but there is no rule that says you have to.

Matching each format separately makes your code quite a bit more readable:

function matchPhoneNumber($phoneNumber) {
    $regex = [
        '/^(?P<prefix>868)(?P<first>\d{3})(?P<second>\d{4})$/',
        '/^(?P<prefix>868)-(?P<first>\d{3})-(?P<second>\d{4})$/',
        '/^(?P<prefix>868)\s(?P<first>\d{3})-(?P<second>\d{4})$/',
        '/^\((?P<prefix>868)\)\s(?P<first>\d{3})\s(?P<second>\d{4})$/',
    ];
    foreach ($regex as $reg) {
        if (preg_match($reg, $phoneNumber, $match) === 1) {
            return $match;
        }
    }
    return false;
}

Answer 6

Assuming PHP uses EREs like awk or grep -E does:

$ grep -E '^((868([0-9]{3}|[- ][0-9]{3}-))|(\(868\) [0-9]{3} ))[0-9]{4}$' file
8680000000
(868) 000 0000
868-000-0000
868 000-0000

or if you like \\d instead of [0-9] :

^((868(\d{3}|[- ]\d{3}-))|(\(868\) \d{3} ))\d{4}$

Anything briefer would match other phone number formats that you didn't specify as being valid and so I'm assuming are invalid.