Expressiveness isn't about saving time discriminating among different options. That's more like a form of simplicity. Expressiveness is a soft quality and is about being able to convey the thought or feeling of an algorithm in a natural way to a human. This helps when you're reading code and when you're conjuring up the code in your head.
Functionally identical patterns of code are not equivalently expressive. Certainly the computer doesn't care, but code is written for humans first and foremost. The more ways I can express a functionally equivalent operation, the more expressive the language is. This is because (ideally) each of the different ways has a unique feeling to it that evokes the right intuition needed in the right contexts.
It appears that we were using different meanings for expressiveness though - yours was focusing on communicating both the feel and the function of the code, mine was focusing on communicating efficiently[1].
I don't think that they're orthogonal, and I'm not sure at the level that "there's only one way to do anything" is normally applied in Python that it negatively effects either, especially since the implied full version seems to be "there's only one way to do anything if you don't have a reason to do differently".
Not that it helps with communicating the feel of an algorithm, but at least it doesn't necessarily hurt. I was only trying to point out that "there's only one way to do things" may not actually be the opposite of expressiveness. Liberally
applied it's possibly neutral or better.
[1] An argument could be made that accurately communicating the feel of the code is the most efficient way to communicate it, although I'm more concerned with the time it takes both to read and to write the code - surely at some point of massaging your code for readability you reach the point diminishing returns :)
Functionally identical patterns of code are not equivalently expressive. Certainly the computer doesn't care, but code is written for humans first and foremost. The more ways I can express a functionally equivalent operation, the more expressive the language is. This is because (ideally) each of the different ways has a unique feeling to it that evokes the right intuition needed in the right contexts.