[nimrody]

Everything that requires a loop and is not expressible using list comprehensions.

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.

[timfi]

This is not strictly true. Python expressions are in fact Turing complete. For example, you can implement an entire Brainfuck interpreter [0] in a single expression.

[0] https://gist.github.com/6bab3480ab439f0e98f18d88750d3b38

[Mixtape]

This is fascinating and absolutely could be its own submission. Excellent work.