ENH: add ignore index to DataFrame / Series.sample

doc/source/whatsnew/v1.3.0.rst

@@ -41,6 +41,7 @@ Other enhancements
 
 - Added :meth:`MultiIndex.dtypes` (:issue:`37062`)
 - Improve error message when ``usecols`` and ``names`` do not match for :func:`read_csv` and ``engine="c"`` (:issue:`29042`)
+- :meth:`DataFrame.sample` now accepts the ``ignore_index`` argument to reset the index after sampling, similar to :meth:`DataFrame.drop_duplicates` and :meth:`DataFrame.sort_values` (:issue:`38581`)
 
 .. ---------------------------------------------------------------------------
 

pandas/core/generic.py

@@ -5134,12 +5134,15 @@ def tail(self: FrameOrSeries, n: int = 5) -> FrameOrSeries:
     @final
     def sample(
         self: FrameOrSeries,
-        n=None,
-        frac=None,
-        replace=False,
-        weights=None,
-        random_state=None,
-        axis=None,
+        n: Optional[int] = None,
+        frac: Optional[float] = None,
+        replace: bool_t = False,
+        weights: Union[str, np.ndarray] = None,
+        random_state: Optional[
+            Union[int, arraylike, np.random.BitGenerator, np.random.RandomState]
+        ] = None,
+        axis: Union[int, str] = None,
+        ignore_index: Optional[bool_t] = False,
     ) -> FrameOrSeries:
         """
         Return a random sample of items from an axis of object.
@@ -5181,6 +5184,10 @@ def sample(
         axis : {0 or ‘index’, 1 or ‘columns’, None}, default None
             Axis to sample. Accepts axis number or name. Default is stat axis
             for given data type (0 for Series and DataFrames).
+        ignore_index : bool
+            If True, the resulting index will be labeled 0, 1, …, n - 1.
+
+            .. versionadded:: 1.3.0
 
         Returns
         -------
@@ -5338,7 +5345,11 @@ def sample(
             )
 
         locs = rs.choice(axis_length, size=n, replace=replace, p=weights)
-        return self.take(locs, axis=axis)
+        result = self.take(locs, axis=axis)
+        if ignore_index:
+            result.index = ibase.default_index(len(result))
+
+        return result
 
     @final
     @doc(klass=_shared_doc_kwargs["klass"])

pandas/tests/generic/methods/test_sample.py

@@ -3,7 +3,7 @@
 
 from pandas.compat.numpy import np_version_under1p17
 
-from pandas import DataFrame, Series
+from pandas import DataFrame, Index, Series
 import pandas._testing as tm
 import pandas.core.common as com
 
@@ -305,3 +305,12 @@ def test_sample_is_copy(self):
 
         with tm.assert_produces_warning(None):
             df2["d"] = 1
+
+    def test_sample_ignore_index(self):
+        # GH 38581
+        df = DataFrame(
+            {"col1": range(10, 20), "col2": range(20, 30), "colString": ["a"] * 10}
+        )
+        result = df.sample(3, ignore_index=True)
+        expected_index = Index([0, 1, 2])
+        tm.assert_index_equal(result.index, expected_index)