ENH: Add ignore_index to Series.drop_duplicates (#50844)

Author: phofl

doc/source/whatsnew/v2.0.0.rst

@@ -161,6 +161,7 @@ Other enhancements
 - Added :meth:`Index.infer_objects` analogous to :meth:`Series.infer_objects` (:issue:`50034`)
 - Added ``copy`` parameter to :meth:`Series.infer_objects` and :meth:`DataFrame.infer_objects`, passing ``False`` will avoid making copies for series or columns that are already non-object or where no better dtype can be inferred (:issue:`50096`)
 - :meth:`DataFrame.plot.hist` now recognizes ``xlabel`` and ``ylabel`` arguments (:issue:`49793`)
+- :meth:`Series.drop_duplicates` has gained ``ignore_index`` keyword to reset index (:issue:`48304`)
 - Improved error message in :func:`to_datetime` for non-ISO8601 formats, informing users about the position of the first error (:issue:`50361`)
 - Improved error message when trying to align :class:`DataFrame` objects (for example, in :func:`DataFrame.compare`) to clarify that "identically labelled" refers to both index and columns (:issue:`50083`)
 - Added :meth:`DatetimeIndex.as_unit` and :meth:`TimedeltaIndex.as_unit` to convert to different resolutions; supported resolutions are "s", "ms", "us", and "ns" (:issue:`50616`)

pandas/core/series.py

@@ -2131,22 +2131,32 @@ def unique(self) -> ArrayLike:  # pylint: disable=useless-parent-delegation
 
     @overload
     def drop_duplicates(
-        self, *, keep: DropKeep = ..., inplace: Literal[False] = ...
+        self,
+        *,
+        keep: DropKeep = ...,
+        inplace: Literal[False] = ...,
+        ignore_index: bool = ...,
     ) -> Series:
         ...
 
     @overload
-    def drop_duplicates(self, *, keep: DropKeep = ..., inplace: Literal[True]) -> None:
+    def drop_duplicates(
+        self, *, keep: DropKeep = ..., inplace: Literal[True], ignore_index: bool = ...
+    ) -> None:
         ...
 
     @overload
     def drop_duplicates(
-        self, *, keep: DropKeep = ..., inplace: bool = ...
+        self, *, keep: DropKeep = ..., inplace: bool = ..., ignore_index: bool = ...
     ) -> Series | None:
         ...
 
     def drop_duplicates(
-        self, *, keep: DropKeep = "first", inplace: bool = False
+        self,
+        *,
+        keep: DropKeep = "first",
+        inplace: bool = False,
+        ignore_index: bool = False,
     ) -> Series | None:
         """
         Return Series with duplicate values removed.
@@ -2163,6 +2173,11 @@ def drop_duplicates(
         inplace : bool, default ``False``
             If ``True``, performs operation inplace and returns None.
 
+        ignore_index : bool, default ``False``
+            If ``True``, the resulting axis will be labeled 0, 1, …, n - 1.
+
+            .. versionadded:: 2.0.0
+
         Returns
         -------
         Series or None
@@ -2225,6 +2240,10 @@ def drop_duplicates(
         """
         inplace = validate_bool_kwarg(inplace, "inplace")
         result = super().drop_duplicates(keep=keep)
+
+        if ignore_index:
+            result.index = default_index(len(result))
+
         if inplace:
             self._update_inplace(result)
             return None

pandas/tests/series/methods/test_drop_duplicates.py

@@ -242,3 +242,10 @@ def test_drop_duplicates_categorical_bool_na(self, nulls_fixture):
             index=[0, 1, 4],
         )
         tm.assert_series_equal(result, expected)
+
+    def test_drop_duplicates_ignore_index(self):
+        # GH#48304
+        ser = Series([1, 2, 2, 3])
+        result = ser.drop_duplicates(ignore_index=True)
+        expected = Series([1, 2, 3])
+        tm.assert_series_equal(result, expected)