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Comment by sarchertech | Hacker News Reader

I love comprehensions as long as they are used in moderation. There’s a tendency for people who just learn them to try to replace every Enum.map.

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I generally default to a comprehension unless it becomes illegible.

Disclaimer: I am the author of the article and am in the pocket of Big Comprehension

Interesting, I use `map` all the time and `for` rarely. I'm not necessarily disagreeing with you as I see this as more of a style preference.

The map approach feels a lot more functional to me and is easy to chain. The `for` method feels a bit awkward. But that said I much prefer Ruby to Python. If I had the opposite preference, I'd probably like the `for` in Elixir more.

I agree with you: I prefer map and reduce unless I specifically need a comprehension because of multiple input collections. IMO for with many conditions etc. becomes too hard to understand, and you have to keep too many things in mind vs. a filter |> map. Regardless, I don't mind its presence, and it definitely has come in handy at times. Yet another reason to enjoy Elixir's approach to language design!

I also use ‘for’ rarely. It silently ignore list elements that don’t match, whereas ‘map’ or ‘each’ blow up. Generally I prefer things to blow up rather than fail silently.

I generally just use for loops but I’m in the pocket of Big Ignorance.

Elixir doesn't have for loops

    for x <- 1..10 do
      IO.puts x
    end

Isn't that a for loop?

In Elixir that is a called a comprehension, just like the blog post is discussing.

Similar, but different in subtle ways when you get beyond the toy example posted here...particularly that it's always iterating a collection, vs being able to just arbitrarily loop based on arbitrary conditions..where you'd be able to easily break out of it, modify a mutable collection within it etc

https://dev.to/brewinstallbuzzwords/does-elixir-have-for-loo... "Does Elixir have for loops?"

https://elixirforum.com/t/changing-variables-in-a-loop/43526 "Changing variables in a loop"

https://stackoverflow.com/questions/56196664/better-way-writ...

https://stackoverflow.com/questions/48178773/adding-items-to...

A real world example of relatively complex filter conditions + flattened transformations simplified with comprehension I usually bring up is: https://github.com/hexpm/bob/blob/177a4354a25cb4f2f2f0349ccd...

I tend to replace most instances of Enum.map with filters. Filters are also easier to read than quite a few instances of Enum.filter or Enum.into, too!

Outside of things like generating a game board, or some other well structured n-dimensional struct, I generally avoid nesting them, though. I’ll use Enum on the outer function(s) and filter for the inner one.

Somehow `for` doesn't read as comprehension to me. In Erlang I used to use comprehensions extensively. In Elixir I almost never do, and only use Enum.map

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