Merge pull request #1097 from cpcloud/ts-fix

Fix issue when converting datetimes and pandas Timestamps in an expression

blaze/compute/pyfunc.py

@@ -1,5 +1,6 @@
 from __future__ import absolute_import, division, print_function
 
+import pandas as pd
 from ..expr import (Expr, Symbol, Field, Arithmetic, Math,
                     Date, Time, DateTime, Millisecond, Microsecond, broadcast,
                     sin, cos, Map, UTCFromTimestamp, DateTimeTruncate, symbol,
@@ -63,7 +64,7 @@ def _print_python(expr, leaves=None):
 
 @dispatch((datetime.datetime, datetime.date))
 def _print_python(expr, leaves=None):
-    return repr(expr), {'datetime': datetime}
+    return repr(expr), {'datetime': datetime, 'Timestamp': pd.Timestamp}
 
 @dispatch(Symbol)
 def _print_python(expr, leaves=None):

blaze/compute/tests/test_pyfunc.py

@@ -43,8 +43,8 @@ def test_datetime_literals_and__print_python():
 
 def test_datetime_literals():
     f = lambdify([t], t.when > '2000-01-01')
-    assert f((1, 0, 3, datetime.datetime(2000, 1, 2))) == True
-    assert f((1, 0, 3, datetime.datetime(1999, 1, 2))) == False
+    assert f((1, 0, 3, datetime.datetime(2000, 1, 2)))
+    assert not f((1, 0, 3, datetime.datetime(1999, 1, 2)))
 
 
 def test_broadcast_collect():

blaze/expr/arithmetic.py

@@ -3,6 +3,7 @@
 import operator
 from toolz import first
 import numpy as np
+import pandas as pd
 from datashape import dshape, var, DataShape
 from dateutil.parser import parse as dt_parse
 from datashape.predicates import isscalar, isboolean, isnumeric
@@ -220,7 +221,7 @@ def scalar_coerce(_, val):
 
 @dispatch(ct.DateTime, _strtypes)
 def scalar_coerce(_, val):
-    return dt_parse(val)
+    return pd.Timestamp(val)
 
 
 @dispatch(ct.CType, _strtypes)

blaze/expr/tests/test_expr.py

@@ -1,7 +1,10 @@
 from __future__ import absolute_import, division, print_function
 
+import pandas as pd
+
 import pytest
-from datashape import dshape
+
+from datashape import dshape, var, datetime_
 
 from blaze.expr import symbol, label, Field
 
@@ -121,3 +124,15 @@ def test_map_with_rename():
     with pytest.raises(ValueError):
         result.relabel(timestamp='date')
     assert result.fields == ['date']
+
+
+def test_hash_to_different_values():
+    s = symbol('s', var * datetime_)
+    expr = s >= pd.Timestamp('20121001')
+    expr2 = s >= '20121001'
+    assert expr2 & expr is not None
+    assert hash(expr) == hash(expr2)
+
+    from blaze.expr.expressions import _attr_cache
+    assert (expr, '_and') in _attr_cache
+    assert (expr2, '_and') in _attr_cache