ENH: Refactor code to add is_view method for Series.

Author: jseabold

pandas/core/series.py

@@ -1645,6 +1645,20 @@ def update(self, other):
  #----------------------------------------------------------------------
  # Reindexing, sorting
 
+ def is_view(self):
+ """
+ Return True if series is a view of some other array, False otherwise.
+ """
+ true_base = self.values
+ while true_base.base is not None:
+ true_base = true_base.base
+
+ if (true_base is not None and
+ (true_base.ndim != 1 or true_base.shape != self.shape)):
+ return True
+ return False
+
+
  def sort(self, axis=0, kind='quicksort', order=None, ascending=True):
  """
  Sort values and index labels by value, in place. For compatibility with
@@ -1667,12 +1681,7 @@ def sort(self, axis=0, kind='quicksort', order=None, ascending=True):
  sortedSeries = self.order(na_last=True, kind=kind,
  ascending=ascending)
 
- true_base = self.values
- while true_base.base is not None:
- true_base = true_base.base
-
- if (true_base is not None and
- (true_base.ndim != 1 or true_base.shape != self.shape)):
+ if self.is_view():
  raise TypeError('This Series is a view of some other array, to '
  'sort in-place you must create a copy')
 

pandas/tests/test_series.py

@@ -5548,6 +5548,13 @@ def test_unique_data_ownership(self):
  # it works! #1807
  Series(Series(["a", "c", "b"]).unique()).sort()
 
+def test_is_view():
+ df = tm.makeDataFrame()
+ view = df['A'].is_view()
+ tm.assert_equal(view, True)
+ ser = tm.makeStringSeries()
+ view = ser.is_view()
+ tm.assert_equal(view, False)
 
 if __name__ == '__main__':
  nose.runmodule(argv=[__file__, '-vvs', '-x', '--pdb', '--pdb-failure'],