Optimize the Dutch telephone number RegEx pattern

Question

This is my current RegEx:

^((\+|00(\s|\s?\-\s?)?)31(\s|\s?\-\s?)?(\(0\)[\-\s]?)?|0)[1-9]((\s|\s?\-\s?)?[0-9])((\s|\s?-\s?)?[0-9])([0-9])\s?[0-9]\s?[0-9]\s?[0-9]\s?[0-9]\s?[0-9]$

These are my test results:

• 0612345678 true
• 06-12345678 true
• +31612345678 true
• +316-12345678 true
• 00316-12345678 true
• 061234567 false
• 06-12-345678 false
• 06-asdfghjk false
• 0331234567 true
• 0345-123456 false
• +31331234567 true
• +3133-1234567 true
• 003133-1234567 true
• 033123456 false
• 010-12-34567 false
• 035-asdfghj false
• 0345-123456 false
• 010-1234567 true

Everything seems ok, but there is one :-) string which needs to be matched (correct telephone number) but the RegEx doesn't match. This is the 0345-123456. Can anybody help me complete (or optimize) my RegEx so that all the above tests are ok?

Thanks for helping!

Answer 1

There are optional whitespace chars in the pattern, but in the example data there are no whitespace chars.

You could write a pattern to match the specific listed formats, and for a match only you can omit the capture groups.

Note that 0345-123456 is 2 times in the list.

^(?:(?:(?:\+|00)31|0)(?:\d-?\d{8}|\d\d-\d{7})|0\d{3}-\d{6})$

• ^ Start of string
• (?: Non capture group
  • (?:(?:\+|00)31|0) Match either +31 or 0031 or 0
  • (?: Non capture group
    • \d-?\d{8} Match a digit, optional - and 8 digits
    • | Or
    • \d\d-\d{7} Match 2 digits - and 7 digits
  • ) Close non capture group
  • | Or
  • 0 Match a single zero
  • \d{3}-\d{6} Match 3 digits - 6 digits
• ) Close the outer non capture group
• $ End of string

Regex demo