Technically flat_map, like reduce are considered base-most enumeration functions. flat_map is the base-most that always returns another enumeration, and reduce is the base-most that returns anything. filter_map is pretty duplicative as I always use flat_map anyways.
OvermindDL1
3
Sleepful
thanks!
[1, 2, 3]
|> Enum.map(&(&1+3))
|> Enum.reject(&(&1==4))
# => [5, 6]
=>
[1, 2, 3]
|> Enum.flat_map(fn n ->
case n+3 do
4 -> []
n -> [n]
end
end)
# => [5, 6]
0
adamu
Hello from the future. The commit log doesn’t mention why it was deprecated, but whatyouhide, a core team member, explained a bit on this issue:
Elixir deprecated the usage of
Enum.filter_map/3because it was counterintuitive and the same could be achieved withEnum.filter/2+Enum.map/2, withStream, or with aforcomprehension.
And also José Valim in the mailing list:
I would use comprehensions:
for item <- 1, 2, 3, rem(item, 2) == 0, do: item * 2There is no reason for Enum.filter_map or Enum.map_filter to exist besides backwards compatibility.
7