Regex with wildcard search? - regex

Question

I created a Regex to check a string for the following situation:
first 4 chars are numbers
following by a point
following by 3 numbers
following by a point
following by 4 to 8 numbers or letters
ie: 1234.123.125B
My Regex: ^[0-9]{4}[.][0-9]{3}[.][0-9a-zA-Z]{4,8}$
But now I need a wildcard search: The Regex should also match if there is a '*' after the first 8 characters. For example:
1234.123.12* MATCH
1234.123* MATCH
1234.123.45B9* MATCH
1234.12* NO MATCH
1234.12345* NO MATCH
How can I add the wildcard search to my Regex?
Thank you

Answer 1

You may use this regex with alternation:
^\d{4}\.\d{3}(?:\*|\.[\da-zA-Z]{0,7}\*|\.[\da-zA-Z]{4,8})$
RegEx Demo
RegEx Details:
^: Start
\d{4}\.\d{3}: Match 4 digits + 1 dot + 3 digits
(?:\*|\.[\da-zA-Z]{0,7}\*|\.[\da-zA-Z]{4,8}): matches a single * OR a * after after a dot and 0 to 7 digits/letters OR match 4 to 8 digits/letters
$: End

Answer 2

My assumptions are that:
You don't allow wildcards to be mid-string
Nor do you want to allow wildcards after the full pattern (e.g.: 1234.123.12345678*).
So, alternatively you may possibily use something like:
^\d{4}\.\d{3}(?!.*\*.)(?![^*]{0,4}$)[.*][*\da-zA-Z]{0,8}$
See the online demo.
^ - Start string ancor.
\d{4}\.\d{3} - Four digits, a dot and another three digits.
(?!.*\*.) - Negative lookahead for zero or more characters followed by asterisk and another character other than newline.
(?![^*]{0,4}$) - Negative lookahead for zero to four characters other than asterisk before end string ancor.
[.*] - A literal dot or asterisk.
[*\da-zA-Z]{0,8} - Zero to eight characters from the character class.
$ - End string ancor.