ENH: Added NDFrame.slice_shift

added slice_shift func docs and removed freq argument

Author: dalejung

pandas/core/generic.py

@@ -3227,6 +3227,42 @@ def shift(self, periods=1, freq=None, axis=0, **kwds):
 
         return self._constructor(new_data).__finalize__(self)
 
+    def slice_shift(self, periods=1, axis=0, **kwds):
+        """
+        Equivalent to `shift` without copying data. The shifted data will
+        not include the dropped periods and the shifted axis will be smaller
+        than the original.
+
+        Parameters
+        ----------
+        periods : int
+            Number of periods to move, can be positive or negative
+
+        Notes
+        -----
+        While the `slice_shift` is faster than `shift`, you may pay for it
+        later during alignment.
+
+        Returns
+        -------
+        shifted : same type as caller
+        """
+        if periods == 0:
+            return self
+
+        if periods > 0:
+            vslicer = slice(None, -periods)
+            islicer = slice(periods, None)
+        else:
+            vslicer = slice(-periods, None)
+            islicer = slice(None, periods)
+
+        new_obj = self._slice(vslicer, axis=axis)
+        shifted_axis = self._get_axis(axis)[islicer]
+        new_obj.set_axis(axis, shifted_axis)
+
+        return new_obj.__finalize__(self)
+
     def tshift(self, periods=1, freq=None, axis=0, **kwds):
         """
         Shift the time index, using the index's frequency if available