How does this account for string casing, i.e uppercase, lowercase?

maybe i'm wrong, but expressions a+bc and cb+a not make sense, how do you think?

In case of in it depends on data structure. Hashmap based set and dict don't iterate items (unless everything has the same hash which is extremely unlikely), but list and tuple do.

Either author should specify that blatant for shouldn't be used or add tests accodringly to your' suggestion.

Good to know thanks!

I think it would be more efficient to save it in a variable rather than calling it multiple times. It's not a big deal here because the lists are small (and maybe you have memory problems if the number is big? idk).
Basically ppl on CW just try to write all their code on one line regardless of efficency (as long as it passes all tests).

Hi, I see a lot of solutions on codewars that use len(x) (or min, lower, count...) in loops or throughout the code rather than doing it once and saving the result in a reusable variable, which I would think is more efficient. Is it not? Why do you use it this way? Readability? Code minimisation?

No, that's incorrect. This test is expected to return False.

yes, tests are wrong.
[3,2,4,2,3,3,3,3,3,3,3,3,3,2,3,3] is expected to return True, which is wrong

This test couldn't check for True because the reference solution returns False for this case.

The random tests for python are not correct, for example:

[2, 3, 3, 3, 3, 3, 1, 3, 3, 3, 2] should be False, but it checks for True

(You can make one row with 2+2 and one row with 1+3, than you have only threes left)