ENH: Allow parameter min_periods in DataFrame.corrwith()

doc/source/whatsnew/v3.0.0.rst

@@ -39,6 +39,7 @@ Other enhancements
 - Users can globally disable any ``PerformanceWarning`` by setting the option ``mode.performance_warnings`` to ``False`` (:issue:`56920`)
 - :meth:`Styler.format_index_names` can now be used to format the index and column names (:issue:`48936` and :issue:`47489`)
 - :class:`.errors.DtypeWarning` improved to include column names when mixed data types are detected (:issue:`58174`)
+- :meth:`DataFrame.corrwith` now accepts ``min_periods`` as optional arguments, as in :meth:`DataFrame.corr` and :meth:`pd.Series.corr` (:issue:`9490`)
 - :meth:`DataFrame.cummin`, :meth:`DataFrame.cummax`, :meth:`DataFrame.cumprod` and :meth:`DataFrame.cumsum` methods now have a ``numeric_only`` parameter (:issue:`53072`)
 - :meth:`DataFrame.fillna` and :meth:`Series.fillna` can now accept ``value=None``; for non-object dtype the corresponding NA value will be used (:issue:`57723`)
 - :meth:`Series.cummin` and :meth:`Series.cummax` now supports :class:`CategoricalDtype` (:issue:`52335`)

pandas/core/frame.py

@@ -11127,6 +11127,7 @@ def corrwith(
         drop: bool = False,
         method: CorrelationMethod = "pearson",
         numeric_only: bool = False,
+        min_periods: int | None = None,
     ) -> Series:
         """
         Compute pairwise correlation.
@@ -11157,6 +11158,9 @@ def corrwith(
         numeric_only : bool, default False
             Include only `float`, `int` or `boolean` data.
 
+        min_periods : int, optional
+            Minimum number of observations needed to have a valid result.
+
             .. versionadded:: 1.5.0
 
             .. versionchanged:: 2.0.0
@@ -11200,7 +11204,10 @@ def corrwith(
         this = self._get_numeric_data() if numeric_only else self
 
         if isinstance(other, Series):
-            return this.apply(lambda x: other.corr(x, method=method), axis=axis)
+            return this.apply(
+                lambda x: other.corr(x, method=method, min_periods=min_periods),
+                axis=axis,
+            )
 
         if numeric_only:
             other = other._get_numeric_data()

pandas/tests/frame/methods/test_cov_corr.py

@@ -461,3 +461,28 @@ def test_corrwith_spearman_with_tied_data(self):
         result = df_bool.corrwith(ser_bool)
         expected = Series([0.57735, 0.57735], index=["A", "B"])
         tm.assert_series_equal(result, expected)
+
+    def test_corrwith_min_periods(self):
+        # GH#9490
+        pytest.importorskip("scipy")
+        df1 = DataFrame(
+            {
+                "A": [1, np.nan, 7, 8],
+                "B": [False, True, True, False],
+                "C": [10, 4, 9, 3],
+            }
+        )
+        df2 = df1[["B", "C"]]
+        result = (df1 + 1).corrwith(df2.B, method="spearman", min_periods=2)
+        expected = Series([0.0, 1.0, 0.0], index=["A", "B", "C"])
+        tm.assert_series_equal(result, expected)
+
+        df_bool = DataFrame(
+            {"A": [True, True, False, False], "B": [True, False, False, True]}
+        )
+        ser_bool = Series([True, True, False, True])
+        result = df_bool.corrwith(ser_bool, min_periods=3)
+        expected = Series(
+            [0.57735, 0.57735], index=["A", "B"]
+        )  # Expected values based on min_periods
+        tm.assert_series_equal(result, expected)

pandas/tests/groupby/test_api.py

@@ -192,6 +192,8 @@ def test_frame_consistency(groupby_func):
         exclude_expected = {"numeric_only"}
     elif groupby_func in ("quantile",):
         exclude_expected = {"method", "axis"}
+    elif groupby_func in ["corrwith"]:
+        exclude_expected = {"min_periods"}
     if groupby_func not in ["pct_change", "size"]:
         exclude_expected |= {"axis"}