Add an IamDataFrame.series attribute to get internal _data

RELEASE_NOTES.md

@@ -1,3 +1,8 @@
+# Next release
+
+- [#989](https://github.com/IAMconsortium/pyam/pull/989) Add an `IamDataFrame.series` attribute to get timeseries data
+  as **pd.Series**
+
 # Release v3.3.3
 
 ## Highlights

pyam/core.py

@@ -433,6 +433,11 @@ def data(self):
             return pd.DataFrame([], columns=self.dimensions + ["value"])
         return self._data.reset_index()
 
+    @property
+    def series(self):
+        """Return the timeseries data as an indexed :class:`pandas.Series`"""
+        return self._data.copy()
+
     def sort_data(self, inplace=False):
         """Sort timeseries data by index and coordinates
 

tests/test_core.py

@@ -332,6 +332,19 @@ def test_print_empty(test_df_year):
     assert obs == exp
 
 
+def test_pandas_types(test_df):
+
+    series = test_df.series
+    data = test_df.data
+
+    # assert that data and series yield the same result as different types
+    pdt.assert_frame_equal(series.reset_index(), data)
+
+    # check that `series` yields a copy and changes to not affect the IamDataFrame
+    series.iloc[0] = -2
+    pdt.assert_frame_equal(test_df.series.reset_index(), data)
+
+
 def test_as_pandas(test_df):
     # test that `as_pandas()` returns the right columns
     df = test_df.copy()