unique check using regex for string separated by comma

Question

so i am trying to come up with a perfect regex for checking a set of predefined string separated by commas without any repeat. Currently i've been able to achive this

^((IN|THE|BUSH|COM|NET|ALL)\s*[,]{0,1}\s*)+$

its works fine for its purpose apart from the fact that its doesn't check for unique values

example is "IN, THE, COM" without quotes this is a correct format

but having this is incorrect

"IN, COM, THE, COM"

i need a regex that works with java for this same task

You're trying to run two *different* validations with a single regex. Don't do it: even if it's possible it's difficult to read & maintain. — Nir Alfasi, Jan 15 '18 at 15:18
right now i don't code that does that in java, am checking with online regex validator, and onces it works i intend to integrate it to my code. Thanks — Ezell Buoee, Jan 15 '18 at 15:18
Once your regex is validated, run another regex check for unique values. You can achieve this with a negative lookahead. See https://stackoverflow.com/questions/40469320/regex-only-match-unique-string-occurrences — Pierre François, Jan 15 '18 at 15:23
I think you're looking for `^(IN|THE|BUSH|COM|NET|ALL)(?!.*\b\1\b)(?:\h*,\h*(IN|THE|BUSH|COM|NET|ALL)(?!.*\b\2\b))*$` — ctwheels, Jan 15 '18 at 15:31
Thanks for you advice @PierreFrançois, my framework will only accept one regex for one field, i cannot custom that — Ezell Buoee, Jan 15 '18 at 15:32
Thans @ctwheels, it works for some inputs only like "THE,IN,COM,NET,THE" but for somethings like this, it doesn't work "THE,IN,COM,NET,NET" so it check for repeatation on the first occurrence only — Ezell Buoee, Jan 15 '18 at 15:37
Sorry, change `\h*` to `\s*` (I needed `\h*` for multiline online) — ctwheels, Jan 15 '18 at 15:41
Thanks @ctwheels u'm it doesn't work for my case, it only check for repeatation on the first occurrence only e.g IN, THE it check for multiple occurrence of IN and not for THE or other sets — Ezell Buoee, Jan 15 '18 at 15:54
@StarBlazh it checks for multiple occurrences regardless of location. — ctwheels, Jan 15 '18 at 15:55

The fourth bird · Accepted Answer · 2018-01-15T16:55:29.627

0

Maybe you can use this regex which uses a negative lookahead (?!.*\1) the check if what is following is not what is captured in the first group \1

^(?:(IN|THE|BUSH|COM|NET|ALL)\h*,?\h*(?!.*\1))+$

edited Jan 15 '18 at 16:55

answered Jan 15 '18 at 16:47

The fourth bird

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Great, works like charm, i wasn't thinking to that direction. Thanks – Ezell Buoee Jan 15 '18 at 17:14
"checking a set of predefined string separated by commas without any repeat." – The fourth bird Jan 15 '18 at 21:26

unique check using regex for string separated by comma

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