fix rounding in pytables query

Author: chris-b1

doc/source/whatsnew/v0.19.0.txt

@@ -1567,7 +1567,7 @@ Bug Fixes
 - Bug in ``DataFrame.to_csv()`` with ``MultiIndex`` columns in which a stray empty line was added (:issue:`6618`)
 - Bug in ``DatetimeIndex``, ``TimedeltaIndex`` and ``PeriodIndex.equals()`` may return ``True`` when input isn't ``Index`` but contains the same values (:issue:`13107`)
 - Bug in assignment against datetime with timezone may not work if it contains datetime near DST boundary (:issue:`14146`)
-- Bug in ``pd.eval()`` truncating long float literals with python 2 (:issue:`14241`)
+- Bug in ``pd.eval()`` and ``HDFStore`` query truncating long float literals with python 2 (:issue:`14241`)
 - Bug in ``Index`` raises ``KeyError`` displaying incorrect column when column is not in the df and columns contains duplicate values (:issue:`13822`)
 - Bug in ``Period`` and ``PeriodIndex`` creating wrong dates when frequency has combined offset aliases (:issue:`13874`)
 - Bug in ``.to_string()`` when called with an integer ``line_width`` and ``index=False`` raises an UnboundLocalError exception because ``idx`` referenced before assignment.

pandas/computation/pytables.py

@@ -611,10 +611,14 @@ def __init__(self, value, converted, kind):
     def tostring(self, encoding):
         """ quote the string if not encoded
             else encode and return """
-        if self.kind == u('string'):
+        if self.kind == u'string':
             if encoding is not None:
                 return self.converted
             return '"%s"' % self.converted
+        elif self.kind == u'float':
+            # python 2 str(float) is not always
+            # round-trippable so use repr()
+            return repr(self.converted)
         return self.converted
 
 

pandas/io/tests/test_pytables.py

@@ -5003,6 +5003,16 @@ def test_read_from_py_localpath(self):
         tm.assert_frame_equal(expected, actual)
 
 
+    def test_query_long_float_literal(self):
+        # GH 14241
+        df = pd.DataFrame([{"A": 1000000000.0099}])
+        cutoff = 1000000000.006
+        with ensure_clean_store(self.path) as store:
+            store.append('test', df, format='table', data_columns=True)
+            result = store.select('test', "A < %.3f" % cutoff)
+        self.assertTrue(result.empty)
+
+
 class TestHDFComplexValues(Base):
     # GH10447