I'm trying to create a regular expression to match on a specific given number pattern.
The patterns are:
123456
1234XX
1234*
Not allowed are:
A combinations like: 1234*X or 1234X*
Or a multiple *: 1234**
I already tried this expression:
/^[\\+\\#\\*0-9]{0,25}[X]*$/
But here I got the multiple * and 1234*X as valid expressions.
Does anyone have an idea of a proper soultion or a way to a solution?
Edit: Ok, I think I should clearify the rules.
The regex should match any given number:
012345
+12345
#1234525
But also match for strings with a X in it.
12345X
12345XX
1234XXXXXX
XXXXXX
The Xs should always stand on the end of the string.
A single * should only be allowed at the end of the string.
1234*
1234556*
1*
Multiple * aren't allowed. Only one * at the end of the string.
The combination of X and * are not allowed. 1234X* or 12345*X are not allowed.
Length restriction: 0 to 25 characters.
You can use
'~^(?=.{0,25}$)[+#]?\d*(?:X*|\*?)$~D'
See regex demo
This will make sure the whole string is 0 to 25 chars long, and will only allow one * at the end of the string, and zero or more X can only follow 0 or more digits.
Details:
^ - start of string(?=.{0,25}$) - a positive lookahead checking the whole string length (must be from 0 to 25 chars long)[+#]? - one or zero + or #\d* - zero or more digits(?:X*|\*?) - a non-capturing group matching either of the 2 alternatives:
X* - zero or more X symbols| - or...\*? - one or zero * symbols$ - end of string (better replace it with \z to ensure no newline at the end is accepted, or just add D modifier).