ENH: Make Series.update() use objects coercible to Series (#33502)

Author: dericke

doc/source/whatsnew/v1.1.0.rst

@@ -98,6 +98,8 @@ Other enhancements
   This can be used to set a custom compression level, e.g.,
   ``df.to_csv(path, compression={'method': 'gzip', 'compresslevel': 1}``
   (:issue:`33196`)
+- :meth:`Series.update` now accepts objects that can be coerced to a :class:`Series`,
+  such as ``dict`` and ``list``, mirroring the behavior of :meth:`DataFrame.update` (:issue:`33215`)
 - :meth:`~pandas.core.groupby.GroupBy.transform` and :meth:`~pandas.core.groupby.GroupBy.aggregate` has gained ``engine`` and ``engine_kwargs`` arguments that supports executing functions with ``Numba`` (:issue:`32854`, :issue:`33388`)
 - :meth:`~pandas.core.resample.Resampler.interpolate` now supports SciPy interpolation method :class:`scipy.interpolate.CubicSpline` as method ``cubicspline`` (:issue:`33670`)
 -

pandas/core/series.py

@@ -2786,7 +2786,7 @@ def update(self, other) -> None:
 
         Parameters
         ----------
-        other : Series
+        other : Series, or object coercible into Series
 
         Examples
         --------
@@ -2824,7 +2824,30 @@ def update(self, other) -> None:
         1    2
         2    6
         dtype: int64
+
+        ``other`` can also be a non-Series object type
+        that is coercible into a Series
+
+        >>> s = pd.Series([1, 2, 3])
+        >>> s.update([4, np.nan, 6])
+        >>> s
+        0    4
+        1    2
+        2    6
+        dtype: int64
+
+        >>> s = pd.Series([1, 2, 3])
+        >>> s.update({1: 9})
+        >>> s
+        0    1
+        1    9
+        2    3
+        dtype: int64
         """
+
+        if not isinstance(other, Series):
+            other = Series(other)
+
         other = other.reindex_like(self)
         mask = notna(other)
 

pandas/tests/series/methods/test_update.py

@@ -56,3 +56,21 @@ def test_update_dtypes(self, other, dtype, expected):
         ser.update(other)
 
         tm.assert_series_equal(ser, expected)
+
+    @pytest.mark.parametrize(
+        "series, other, expected",
+        [
+            # update by key
+            (
+                Series({"a": 1, "b": 2, "c": 3, "d": 4}),
+                {"b": 5, "c": np.nan},
+                Series({"a": 1, "b": 5, "c": 3, "d": 4}),
+            ),
+            # update by position
+            (Series([1, 2, 3, 4]), [np.nan, 5, 1], Series([1, 5, 1, 4])),
+        ],
+    )
+    def test_update_from_non_series(self, series, other, expected):
+        # GH 33215
+        series.update(other)
+        tm.assert_series_equal(series, expected)