Exactly. It shouldn't pass. But it is allowed in some solutions I'm seeing. That would help people to achieve the right solution.

Marked as resolved.

Test with "a.b" doesn't pass.

Nope. It's still not resolved. You need to make a new reply and mark the checkbox below the comment box.

Thanks. I edited my previous comment and marked the issue as solved. Did that do it? I did not receive any feedback that it worked and the comment keeps marked as "Issue" in red.

I got it. Thanks for help.

An additional test case shouldbe added: Assert.IsFalse(IdentifierChecker.IsValid("a.b"), "IsValid("a.b") should returns false");
Several people are using the dot sign incorrectly.

You should resolve thte issue if the problem has been solved.

Indeed, even the definitions of alpha and digit are missing. Can identifiers use é? It's an "alpha" character...

The "In other words, it can be any valid identifier character." portion of the instructions will vary based upon language.

In Python, the tests fail because of some syntax error... I get:

  File "", line 14
    Test.describe("isValid")
       ^
SyntaxError: invalid syntax

In Javascript searching for an item in array is o(n). I didnt create the python translation or solution, only the js one, so I cant help you out there, sorry.

Oops, my bad, I meant to say "also O(1) but has higher constants" ... Are javascript's arrays really O(n) for lookup? I have almost 0 experience with that language, so I didn't know. So weird =/

Anyway, did you have time to look at my proposed solution? Almost a week has passed and I still don't see how that took longer than the working solution.