How I can validate this pattern using regex

Question

I try to write a regex to validate a pattern, but I have some problems. This the pattern that I should get and validate using a regex

XXXX
XXXX-XXXX
XXXX-XXXX-XXXX-XXXX-XXXX

Every X is an Int number [0-9]

I'm trying with this :

[0-9]{4}(-?[0-9]{4})?

but it gives me this pattern :

**4586-4584**-**5588-5558**-**5888-5545**

Any idea how to fix this problem? Thanks in advance!

Answer 1

Your pattern [0-9]{4}(-?[0-9]{4})? uses an optional hyphen -? and an optional group (-?[0-9]{4}).

The optional hyphen -? will allow for example 8 digits in a row (4 digits followed by 4 digits).

The optional group will allow only 0 or 1 occurances so XXXX-XXXX-XXXX will not match.

Not using anchors for the beginning and the end of the line, will match 3333-3333 in 333-3333-3333.

You could update your regex to ^[0-9]{4}(-[0-9]{4})*$, or with \d: ^\d{4}(?:-\d{4})*$

Explanation

• From the beginning of the string ^
• 4 digits \d{4}
• A non capturing group to match a hyphen and 4 digits (?:-\d{4})
• Repeat that group zero or more times *
• The end of the string $

Answer 2

[0-9]{4}(-[0-9]{4})*

try this one, you need -, can't add ? ahead it. add * instead of ?, because may have more than one

(?<![0-9\-])[0-9]{4}(-[0-9]{4})*(?![0-9\-])

this one will not match 1234-5667-78961234

Answer 3

^(\d{4})(-(\d{4})){0,5}$

If I understood correctly, you're looking for a pattern of XXXX (so every X is a digit) that appears 1 to 6 times, with hyphens in between.

Hence, the first 4 digits are mandatory, and then it's possible to have 1 to 5 appearances of -XXXX.

Note the ^ and the $, that make sure the regex doesn't match only a part of a string.

Answer 4

Try with this pattern:

    (\b([0-9]){4}\b)|(\b([0-9]){4}\-([0-9]){4}\b)|(\b([0-9]){4}\-([0-9]){4}\-([0-9]){4}\b)|(\b([0-9]){4}\-([0-9]){4}\-([0-9]){4}\-([0-9]){4}\b)

Demo

Answer 5

This should do it. Only tried it using C# though.

[0-9]{4}-[0-9]{4}-[0-9]{4}-[0-9]{4}-[0-9]{4}