What you're saying, then, is that it's terribly confusing [for you] when someone uses a list comprehension fully?
Presumably, these also are not completely clear to you:
> [x * 2 | x <- [1, 2, 3, 4], even x]
[4,8]
> [x * 2 | x <- filter even [1, 2, 3, 4]]
[4,8]
To say that a pretty uncluttered list comprehension is some challenge to read is just hyperbolic. These pipelines, even with newlines, can get pretty long and terrible too.
I was not trying to illustrate that the backslash made it ugly (I've removed it - I was pasting from a repl). It's ugly because of Python's lambda syntax and the fact it does not compose 'sensibly', as compared to fluid interfaces. The logic is back-to-front for one.
> But the list comprehension version is just completely wrong:
No, it's not at all wrong. Your one-liner is not better and (I hope) would probably upset most teams for being less clear.
I was providing a like-for-like example. The multi-lining is not the criticism of the Python version. It's the composition that's at fault, the fact it does not feel like 'two coherent operations over a list' with two distinct conditionals.
The ES5/ES6 examples demonstrate this much more clearly IMO.