Merge pull request #7303 from cpcloud/eval-local-string-fix-7300

BUG: do not remove temporaries from eval/query scope

Author: cpcloud

doc/source/v0.14.1.txt

@@ -71,3 +71,6 @@ Bug Fixes
  and ``left`` keyword is specified (:issue:`7226`)
 - BUG in ``DataFrame.hist`` raises ``TypeError`` when it contains non numeric column (:issue:`7277`)
 - BUG in ``Index.delete`` does not preserve ``name`` and ``freq`` attributes (:issue:`7302`)
+- Bug in ``DataFrame.query()``/``eval`` where local string variables with the @
+ sign were being treated as temporaries attempting to be deleted
+ (:issue:`7300`).

pandas/computation/expr.py

@@ -340,12 +340,10 @@ def _rewrite_membership_op(self, node, left, right):
  # pop the string variable out of locals and replace it with a list
  # of one string, kind of a hack
  if right_str:
- self.env.remove_tmp(right.name)
  name = self.env.add_tmp([right.value])
  right = self.term_type(name, self.env)
 
  if left_str:
- self.env.remove_tmp(left.name)
  name = self.env.add_tmp([left.value])
  left = self.term_type(name, self.env)
 

pandas/computation/scope.py

@@ -278,16 +278,6 @@ def add_tmp(self, value):
  # only increment if the variable gets put in the scope
  return name
 
- def remove_tmp(self, name):
- """Remove a temporary variable from this scope
-
- Parameters
- ----------
- name : str
- The name of a temporary to be removed
- """
- del self.temps[name]
-
  @property
  def ntemps(self):
  """The number of temporary variables in this scope"""

pandas/tests/test_frame.py

@@ -13685,6 +13685,18 @@ def test_query_single_element_booleans(self):
  for parser, engine in product(PARSERS, ENGINES):
  yield self.check_query_single_element_booleans, parser, engine
 
+ def check_query_string_scalar_variable(self, parser, engine):
+ tm.skip_if_no_ne(engine)
+ df = pd.DataFrame({'Symbol': ['BUD US', 'BUD US', 'IBM US', 'IBM US'],
+ 'Price': [109.70, 109.72, 183.30, 183.35]})
+ e = df[df.Symbol == 'BUD US']
+ symb = 'BUD US'
+ r = df.query('Symbol == @symb', parser=parser, engine=engine)
+ tm.assert_frame_equal(e, r)
+
+ def test_query_string_scalar_variable(self):
+ for parser, engine in product(['pandas'], ENGINES):
+ yield self.check_query_string_scalar_variable, parser, engine
 
 class TestDataFrameEvalNumExprPandas(tm.TestCase):