(func(a) for a in collection)
map(func, collection)
[func(a) for a in collection]
list(map(func, collection))
I believe the documentation for `filter` even mentions that it is equivalent to the comprehension[1].
I think this is the case, for me map is much harder to read. But I also think that comprehensions go back to math sets, so I was familiar with this even before learning any programming. Therefore comprehensions clicked immediately for me and it's by far my favourite python feature.
map or filter are much easier to read for complex data manipulations and as a bonus, their composition rules make it easy to increase performance. For example, if you see two map functions together, you can wrap them in a compose and only map over your elements once. This isn't as immediately obvious when you're using comprehensions.
Do you mean something like
> [ manager.name for manager in set([ person.manager for person in employees ])]
?
I assume with something like set() or unique() you need to create the intermediate iterable anyway, but without it I have trouble finding an example where doing a single list comprehension wouldn't suffice.
(1) It's easier to read, particularly for people who don't always think in terms of functional programming.
(2) It's faster, particularly if you have to construct a lambda for the function in apply, map, or filter.
From other perceptive, these usually bother me when my functions are larger, and ideally functions should be small. So I take it as sign that I should probably break down my function.
And yeah, tail calls! I expect that from a modern language with functional programming features. Unfortunately it seems there are no plans to add them in Python
[(foo(a), bar(a)) for a in collection if condition(a) or alt(a)]
foo_bar = lambda x: (foo(x), bar(x))
condition_or_alt = lambda x: condition(x) or alt(x)
map(foo_bar, filter(condition_or_alt, collection))
Comprehensions are one fairly easy way of thinking about sets of things, and transformations of those sets of things. It may not be your preferred way to think about them, but that doesn't mean it's unneeded or that people are wrong to prefer another way.