Unary plus operator (Issue #16073)

doc/source/whatsnew/v0.20.0.txt

@@ -213,8 +213,7 @@ See :ref:`the docs here <io.pickle.compression>`
 
 Using an explicit compression type
 
-.. ipython:: python
-
+.. ipython:: python 
    df.to_pickle("data.pkl.compress", compression="gzip")
    rt = pd.read_pickle("data.pkl.compress", compression="gzip")
    rt
@@ -1196,6 +1195,8 @@ Other API Changes
 - ``DataFrame`` and ``Panel`` constructors with invalid input will now raise ``ValueError`` rather than ``pandas.core.common.PandasError``, if called with scalar inputs and not axes; The exception ``PandasError`` is removed as well. (:issue:`15541`)
 - The exception ``pandas.core.common.AmbiguousIndexError`` is removed as it is not referenced (:issue:`15541`)
 
+- ``Series`` and ``DataFrame`` now have unary plus operators (:issue:`16073`). The plus operator behaves consistently with the unary minus operator. 
+
 
 .. _whatsnew_0200.privacy:
 

pandas/core/generic.py

@@ -859,6 +859,19 @@ def _indexed_same(self, other):
         return all([self._get_axis(a).equals(other._get_axis(a))
                     for a in self._AXIS_ORDERS])
 
+    def __pos__(self):
+        values = _values_from_object(self)
+        if values.dtype == np.bool_:
+            arr = values 
+        else:
+            if (len(values) > 0):
+                try:
+                    -values[0]
+                except TypeError:
+                    raise TypeError("`+` only works on data types that support `-`")
+            arr = operator.pos(values)
+        return self.__array_wrap__(arr)    
+
     def __neg__(self):
         values = _values_from_object(self)
         if values.dtype == np.bool_:

pandas/tests/frame/test_operators.py

@@ -343,9 +343,15 @@ def test_logical_with_nas(self):
         expected = Series([True, True])
         assert_series_equal(result, expected)
 
+    def test_pos(self):
+        try:
+            assert_frame_equal(+self.frame, self.frame.apply(lambda x: +self.frame))
+        except TypeError:
+            if not (len(self.frame) > 0 and isinstance(self.frame[0], pd.Timestamp)):
+                raise
+
     def test_neg(self):
-        # what to do?
-        assert_frame_equal(-self.frame, -1 * self.frame)
+        assert_frame_equal(-self.frame, self.frame.apply(lambda x: -self.frame))
 
     def test_invert(self):
         assert_frame_equal(-(self.frame < 0), ~(self.frame < 0))

pandas/tests/series/test_operators.py

@@ -91,8 +91,15 @@ def check(series, other, check_reverse=False):
         check(self.ts, 5, check_reverse=True)
         check(tm.makeFloatSeries(), tm.makeFloatSeries(), check_reverse=True)
 
+    def test_pos(self):
+       try:
+           assert_series_equal(+self.series, self.series.apply(lambda x: +x))
+       except TypeError:
+           if not (len(self.frame) > 0 and isinstance(self.frame[0], pd.Timestampe)):
+               raise
+
     def test_neg(self):
-        assert_series_equal(-self.series, -1 * self.series)
+        assert_series_equal(-self.series, self.series.apply(lambda x: -x))
 
     def test_invert(self):
         assert_series_equal(-(self.series < 0), ~(self.series < 0))