Really? I find that one line far more pleasant than the Python example above it, with variables being assigned, etc. Both are quite clear in their intention, I think, assuming you recognize "join".
I don't even recognize the language of the one-liner, but it makes perfect sense to me as a reader. It looks like a Perlish solution, but the string method is strange, I think. Maybe Perl 6 or Ruby?
The one-liner is valid Python. It's slightly non-idiomatic in that it uses a list-comprehension where a generator expression would do, and uses range instead of xrange (in Python 2.x; in 3.x range is the idiomatic alternative).
Yes, a ternary would be clearer, to me. I wasn't sure what was happening with the * (and thought maybe it was some use of the "whatever star" in Perl 6, when I was thinking it might be Perl 6, though it doesn't look like any use of the whatever star I've seen), but I just assumed it made sense to someone who knew the language well. It's been a decade since I worked in Python with any regularity.
I would probably use a named function call in real code, but the 'text * (expr == 0)' idiom is pretty clear to me as a way to conditionally include text based on whether a condition is true or not.
I don't even recognize the language of the one-liner, but it makes perfect sense to me as a reader. It looks like a Perlish solution, but the string method is strange, I think. Maybe Perl 6 or Ruby?