Add implementation for tshift (#1016)

* Add implementation for `tshift` * Resolves #1015 * Add implementation for `tshift` * Update and improve tests * Update Documentation
modin-project · Jan 19, 2020 · 32490fb · 32490fb
1 parent 8a1dea1
commit 32490fb
Show file tree

Hide file tree

Showing 4 changed files with 12 additions and 9 deletions.
diff --git a/docs/UsingPandasonRay/dataframe_supported.rst b/docs/UsingPandasonRay/dataframe_supported.rst
@@ -439,7 +439,7 @@ default to pandas.
 +---------------------------+---------------------------------+----------------------------------------------------+
 | `truncate`_               | D                               |                                                    |
 +---------------------------+---------------------------------+----------------------------------------------------+
-| `tshift`_                 | D                               |                                                    |
+| `tshift`_                 | Y                               |                                                    |
 +---------------------------+---------------------------------+----------------------------------------------------+
 | `tz_convert`_             | Y                               |                                                    |
 +---------------------------+---------------------------------+----------------------------------------------------+

diff --git a/modin/pandas/base.py b/modin/pandas/base.py
@@ -3148,7 +3148,9 @@ def truncate(self, before=None, after=None, axis=None, copy=True):
         )
 
     def tshift(self, periods=1, freq=None, axis=0):
-        return self._default_to_pandas("tshift", periods=periods, freq=freq, axis=axis)
+        axis = self._get_axis_number(axis)
+        new_labels = self.axes[axis].shift(periods, freq=freq)
+        return self.set_axis(new_labels, axis=axis, inplace=False)
 
     def transform(self, func, axis=0, *args, **kwargs):
         kwargs["is_transform"] = True

diff --git a/modin/pandas/test/test_dataframe.py b/modin/pandas/test/test_dataframe.py
@@ -2619,10 +2619,10 @@ def test_truncate(self):
 
     def test_tshift(self):
         idx = pd.date_range("1/1/2012", periods=5, freq="M")
-        df = pd.DataFrame(np.random.randint(0, 100, size=(len(idx), 4)), index=idx)
-
-        with pytest.warns(UserWarning):
-            df.to_period().tshift()
+        data = np.random.randint(0, 100, size=(len(idx), 4))
+        modin_df = pd.DataFrame(data, index=idx)
+        pandas_df = pandas.DataFrame(data, index=idx)
+        df_equals(modin_df.tshift(4), pandas_df.tshift(4))
 
     def test_tz_convert(self):
         modin_idx = pd.date_range(

diff --git a/modin/pandas/test/test_series.py b/modin/pandas/test/test_series.py
@@ -2600,9 +2600,10 @@ def test_truncate(data):
 
 def test_tshift():
     idx = pd.date_range("1/1/2012", periods=5, freq="M")
-    modin_series = pd.Series(np.random.randint(0, 100, size=len(idx)), index=idx)
-    with pytest.warns(UserWarning):
-        modin_series.to_period().tshift()
+    data = np.random.randint(0, 100, size=len(idx))
+    modin_series = pd.Series(data, index=idx)
+    pandas_series = pandas.Series(data, index=idx)
+    df_equals(modin_series.tshift(4), pandas_series.tshift(4))
 
 
 def test_tz_convert():