RegEx pattern for comma separated 10 currencies in URI parameter

Question

I need to pass a list of comma separated currencies as URI parameter.

I need a regEx to allow only capital letters in group of three, separated by comma, and that does not allow any white space character.

I tried ((?=\S)[A-Z\s\,]){3,39}+$ regEx

It is working fine for input like: USD, ,J

But it start falling for input like : USD, ,JPY

Answer 1

Use:

^[A-Z]{3}(?:,[A-Z]{3}){0,9}$

This will match 1 upto 10 currencies comma separated

Explanation:

[A-Z]{3}        # 3 letters
(?:             # start non capture group
    ,           # a comma
    [A-Z]{3}    # 3 letters
){0,9}          # end group, may appear 0 upto 9 times