| Before Ruby introduced filter_map: res = (1..10).select { |x| x != 5 }.map { |x| x ** 2 } With filter_map: res = (1..10).filter_map { |x| x ** 2 if x != 5 } In both cases, I think the Ruby solution is more readable. Python list comprehensions invert the subject (data) and the verb (action). You see what will be done before you see what the subject is. I would argue that showing the subject first allows easier code review as you know immediately what you are working with. But beyond that, the first Ruby example tells you in English what is happening. "take this range", "select a subset", then "map some actions to the elements". And the filter_map abbreviation does the same, telling you "take this range, filter it and perform an operation on the remaining elements". Python tells you nothing... and what it does say is in awkward order. As functional and data-oriented programming is gaining in popularity (for good reason), adopting some functional practices in Ruby is a pleasant experience. Doing the same in Python exposes more of these... irregularities. Edit - I always forget how to format symbols in these comments! |
It uses what people already know: the for something in somethings syntax of the for loop, and the if syntax. Also it's nice that this works in dictionaries, generators and lists.
It also has the same narrative flow of Haskell's list comprehensions, which I think come from set theory:
As for your Ruby examples: I think you could argue that the filter_map version is very readable, but not necessarily more so, but the select one looks pretty painful.