['<','='][n==0]
That was impressive.

The answer is in the error itself: you're trying to use toLowerCase on undefined. It's clearly not a string.

I keep gettin 'TypeError: Cannot read property 'toLowerCase' of undefined' even though I'm using the method with a string. The code works just fine when I test it in the console; what could the problem be ?

Thank you for the hint, you helped me a lot =)

You can look at the tests by printing the input:

Troubleshooting - print the input

For this kata, therefore, if you type:

print(title, minor_words)

in your function, you'll be able to read in console which inputs you are failing on.

As for tests 6 and 9 here, just to get you started: you will find that test#6 is using ab as input title and ab as input minor_words; it is expecting Ab as output not ab - Why? Because if you re-read the kata description:

"(b) considered to be an exception and put entirely into lower case unless it is the first word, which is always capitalised."

so you should always capitalise the first word, regardless of whether it appears in the "exception" words or not.

(Python) I have an error in the 6th and 9th test. The sixth test 'ab' should equal 'Ab' and the ninth test 'First of in' should equal 'First Of In' . All other tests are good . Since there is no place to look at these tests, I can't understand what's the matter. Who had a plug in this place, who can tell me?

I agree, the description is disgusting, I've read it 10 times and I don't understand what they want from us. It would be good for the author to give more understandable examples and descriptions.

and here it was a shame!)))

Here you only need your own logic of thinking =) There are many solutions to this kata, the more experience in programming, the more concise the code turns out.

0 does not return, it gives an error, but in general it is brilliant :-)

Not a kata issue, your code mutates the input list, as the error's message says. Read this too: https://docs.codewars.com/training/troubleshooting/#post-discourse

Do you mean string concatenation?