Let {:datetime, _} be an alias for {:naive_datetime, _} for backwards compatibility

lib/explorer/data_frame.ex

@@ -2863,10 +2863,10 @@ defmodule Explorer.DataFrame do
         LazySeries.new(:lazy, [date], :date)
 
       naive_datetime = %NaiveDateTime{} ->
-        LazySeries.new(:lazy, [naive_datetime], {:naive_datetime, :nanosecond})
+        LazySeries.new(:lazy, [naive_datetime], {:naive_datetime, :microsecond})
 
-      datetime = %DateTime{} ->
-        LazySeries.new(:lazy, [datetime], {:datetime, :nanosecond})
+      datetime = %DateTime{time_zone: time_zone} ->
+        LazySeries.new(:lazy, [datetime], {:datetime, :microsecond, time_zone})
 
       duration = %Explorer.Duration{precision: precision} ->
         LazySeries.new(:lazy, [duration], {:duration, precision})

lib/explorer/series.ex

@@ -30,7 +30,7 @@ defmodule Explorer.Series do
   and compatibility with the Elixir ecosystem:
 
     * All numeric dtypes (signed integer, unsigned integer, and floats) can
-      be specified as an atom in the form of `:s32`, `:u8`, `:f32` and o son
+      be specified as an atom in the form of `:s32`, `:u8`, `:f32` and so on
     * The atom `:float` as an alias for `{:f, 64}` to mirror Elixir's floats
     * The atom `:integer` as an alias for `{:s, 64}` to mirror Elixir's integers
 
@@ -370,7 +370,7 @@ defmodule Explorer.Series do
   A list of `Date`, `Time`, `NaiveDateTime`, `DateTime`, and
   `Explorer.Duration` structs are also supported, and they will become series
   with the respective dtypes: `:date`, `:time`, `{:naive_datetime, :microsecond}`,
-  and `{:duration, precision}`.
+  `{:datetime, :microsecond, time_zone}` and `{:duration, precision}`.
   For example:
 
       iex> Explorer.Series.from_list([~D[0001-01-01], ~D[1970-01-01], ~D[1986-10-13]])

lib/explorer/shared.ex

@@ -2,6 +2,8 @@ defmodule Explorer.Shared do
   # A collection of **private** helpers shared in Explorer.
   @moduledoc false
 
+  require Logger
+
   @integer_types [
     {:s, 8},
     {:s, 16},
@@ -87,6 +89,16 @@ defmodule Explorer.Shared do
   def normalise_dtype(:u32), do: {:u, 32}
   def normalise_dtype(:u64), do: {:u, 64}
 
+  def normalise_dtype({:datetime, precision}) do
+    :ok =
+      Logger.warning("""
+      The `{:datetime, _}` dtype has been deprecated.
+      Please use `{:naive_datetime, _}` instead.
+      """)
+
+    {:naive_datetime, precision}
+  end
+
   def normalise_dtype(_dtype), do: nil
 
   @doc """

test/explorer/series_test.exs

@@ -5,6 +5,8 @@ defmodule Explorer.SeriesTest do
 
   alias Explorer.Series
 
+  import ExUnit.CaptureLog
+
   doctest Explorer.Series
 
   test "defines doc metadata" do
@@ -286,6 +288,29 @@ defmodule Explorer.SeriesTest do
                dates
     end
 
+    test "with naive datetimes aliased" do
+      naive_datetimes = [
+        ~N[2022-04-13 15:44:31.560227],
+        ~N[1022-01-04 21:18:31.224123],
+        ~N[1988-11-23 06:36:16.158432],
+        ~N[2353-03-07 00:39:35.702789]
+      ]
+
+      dtype_alias = {:datetime, :microsecond}
+      dtype_actual = {:naive_datetime, :microsecond}
+
+      {series, warning} =
+        with_log(fn -> Series.from_list(naive_datetimes, dtype: dtype_alias) end)
+
+      assert Series.to_list(series) == naive_datetimes
+      assert Series.dtype(series) == dtype_actual
+
+      assert warning =~ """
+             The `{:datetime, _}` dtype has been deprecated.
+             Please use `{:naive_datetime, _}` instead.
+             """
+    end
+
     test "with 32-bit integers" do
       for dtype <- [:s32, {:s, 32}] do
         s = Series.from_list([-1, 0, 1, 2, 3, nil], dtype: dtype)