Skip to content

Optimize Enum.into/2 and Enum.into/3 #14774

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 3 commits into from
Sep 16, 2025
Merged

Optimize Enum.into/2 and Enum.into/3 #14774

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
ace7e5e
Optimize Enum.into(struct, map, fun)
sabiwara Sep 16, 2025
3898098
Optimize Enum.into(enum, map_set)
sabiwara Sep 16, 2025
2759d12
Optimize Enum.into(enum, map_set, fun)
sabiwara Sep 16, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
16 changes: 14 additions & 2 deletions lib/elixir/lib/enum.ex
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1496,6 +1496,14 @@ defmodule Enum do
to_list(enumerable)
end

def into(enumerable, collectable) when is_struct(collectable, MapSet) do
if MapSet.size(collectable) == 0 do
MapSet.new(enumerable)
else
MapSet.new(enumerable) |> MapSet.union(collectable)
end
end

def into(%_{} = enumerable, collectable) do
into_protocol(enumerable, collectable)
end
Expand Down Expand Up @@ -1572,8 +1580,12 @@ defmodule Enum do
map(enumerable, transform)
end

def into(%_{} = enumerable, collectable, transform) do
into_protocol(enumerable, collectable, transform)
def into(enumerable, collectable, transform) when is_struct(collectable, MapSet) do
if MapSet.size(collectable) == 0 do
MapSet.new(enumerable, transform)
else
MapSet.new(enumerable, transform) |> MapSet.union(collectable)
end
end

def into(enumerable, %_{} = collectable, transform) do
Expand Down
9 changes: 9 additions & 0 deletions lib/elixir/test/elixir/enum_test.exs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -455,6 +455,10 @@ defmodule EnumTest do
assert Enum.into(%{a: 1, b: 2}, []) |> Enum.sort() == [a: 1, b: 2]
assert Enum.into(1..3, []) == [1, 2, 3]
assert Enum.into(["H", "i"], "") == "Hi"

assert Enum.into([a: 1, b: 2], MapSet.new()) == MapSet.new(a: 1, b: 2)
assert Enum.into(%{a: 1, b: 2}, MapSet.new()) == MapSet.new(a: 1, b: 2)
assert Enum.into([a: 1, b: 2], MapSet.new(a: 1, c: 3)) == MapSet.new(a: 1, b: 2, c: 3)
end

test "into/2 exceptions" do
Expand All @@ -475,6 +479,9 @@ defmodule EnumTest do
assert Enum.into([1, 2, 3], [], fn x -> x * 2 end) == [2, 4, 6]
assert Enum.into([1, 2, 3], "numbers: ", &to_string/1) == "numbers: 123"

assert Enum.into([1, 2, 3], MapSet.new(), &(&1 * 2)) == MapSet.new([2, 4, 6])
assert Enum.into([1, 2, 3], MapSet.new([0, 2]), &(&1 * 2)) == MapSet.new([0, 2, 4, 6])

assert_raise MatchError, fn ->
Enum.into([2, 3], %{a: 1}, & &1)
end
Expand Down Expand Up @@ -2039,11 +2046,13 @@ defmodule EnumTest.Range do

test "into/2" do
assert Enum.into(1..5, []) == [1, 2, 3, 4, 5]
assert Enum.into(1..5, MapSet.new()) == MapSet.new([1, 2, 3, 4, 5])
end

test "into/3" do
assert Enum.into(1..5, [], fn x -> x * 2 end) == [2, 4, 6, 8, 10]
assert Enum.into(1..3, "numbers: ", &to_string/1) == "numbers: 123"
assert Enum.into(1..3, MapSet.new(), &(&1 * 2)) == MapSet.new([2, 4, 6])
end

test "join/2" do
Expand Down