What *can't* you do in a single line of Python? ♥
Really for one liners, Ruby (or even Perl) are much better. Python with its significant whitespace is a lot less convenient.
The only advantage of Python is that it exists in the default installation usually - unlike Ruby.
[0] https://gist.github.com/6bab3480ab439f0e98f18d88750d3b38