allow only numbers AND may 'contain' slash AND must not start or end with slash

Question

what I have is this:

[^\/][\d]*[^\/]

The problem I still have is: slash at the beginning is still allowed

Anyone an idea?

Thanks in advance

Answer 1

The [^/] matches any char, not just a digit. Besides, to validate a whole string, you need to use anchors, or a method that anchors the match at start and end of the string.

You may use

^(?!\/)[\d\/]*$(?<!\/)

Or

^\d(?:[\/\d]*\d)?$

See the regex demo #1 and regex demo #2.

Regex #1 details

• ^ - start of string
• (?!\/) - no / allowed at the start
• [\d\/]* - 0 or more digits or slashes
• $- end of string
• (?<!\/) - fail the match if there is a / at the end.

Regex #2 details

• ^ - start of string
• \d - a digit
• (?:[\/\d]*\d)? - an optional non-capturing group matching 0 or more / or digit chars and then a digit
• $ - end of string.