My regex: ([a-zA-Z],? *)+
The desired input is something like "A, B, C, D". But of course I want to allow input where the letters aren't capitalized, or there's more than one space between a letter+comma, or no space, etc.
Here's the regex I have, but it's not quite right because input such as "A B C D" is still considered valid.
([a-zA-Z],? *)+ which as I understand it (I'm new to regex) means: contains any letter from a to z, case insensitive, followed by zero or one comma, followed by 0 or more space(s), and then 1 or more of this entire pattern.
Now the issue I think has to do with the "zero or one comma" because I want to allow the input to have multiple letters eg. "A, B, C" but the last character shouldn't be followed by a comma, because that's weird. It also needs to match with single letter input which doesn't have a comma either. So what I want is it to be like a letter followed by a comma only if this isn't the last letter or the only letter... but I don't know how to do that with regex.
EDIT: Here is a new regex I made. I think this works: ([a-zA-Z] *, *)*([a-zA-Z] *)