BUG: Series arithmetic operator cannot handle constant and ndarray #2574

Author: changhiskhan

pandas/core/series.py

@@ -245,7 +245,16 @@ def _flex_method(op, name):
 
  @Appender(doc)
  def f(self, other, level=None, fill_value=None):
- return self._binop(other, op, level=level, fill_value=fill_value)
+ if isinstance(other, Series):
+ return self._binop(other, op, level=level, fill_value=fill_value)
+ elif isinstance(other, (np.ndarray, list, tuple)):
+ if len(other) != len(self):
+ raise ValueError('Lengths must be equal')
+ return self._binop(Series(other, self.index), op,
+ level=level, fill_value=fill_value)
+ else:
+ return Series(op(self.values, other), self.index,
+ name=self.name)
 
  f.__name__ = name
  return f

pandas/tests/test_series.py

@@ -1478,6 +1478,23 @@ def test_all_any(self):
  self.assert_(not bool_series.all())
  self.assert_(bool_series.any())
 
+ def test_op_method(self):
+ def _check_op(series, other, op, alt):
+ result = op(series, other)
+ expected = alt(series, other)
+ tm.assert_almost_equal(result, expected)
+
+ def check(series, other):
+ simple_ops = ['add', 'sub', 'mul']
+
+ for opname in simple_ops:
+ _check_op(series, other, getattr(Series, opname),
+ getattr(operator, opname))
+
+ check(self.ts, self.ts * 2)
+ check(self.ts, self.ts[::2])
+ check(self.ts, 5)
+
  def test_operators(self):
 
  def _check_op(series, other, op, pos_only=False):