MAINT: Enforce string type for where parameter

doc/source/whatsnew/v0.20.0.txt

@@ -812,6 +812,7 @@ Removal of prior version deprecations/changes
 - The ``Categorical`` constructor has dropped the ``name`` parameter (:issue:`10632`)
 - The ``take_last`` parameter has been dropped from ``duplicated()``, ``drop_duplicates()``, ``nlargest()``, and ``nsmallest()`` methods (:issue:`10236`, :issue:`10792`, :issue:`10920`)
 - ``Series``, ``Index``, and ``DataFrame`` have dropped the ``sort`` and ``order`` methods (:issue:`10726`)
+- Where clauses in ``pytables`` are only accepted as strings and expressions types and not other data-types (:issue:`12027`)
 - The ``LongPanel`` and ``WidePanel`` classes have been removed (:issue:`10892`)
 
 .. _whatsnew_0200.performance:

pandas/computation/pytables.py

@@ -1,9 +1,7 @@
 """ manage PyTables query interface via Expressions """
 
 import ast
-import warnings
 from functools import partial
-from datetime import datetime, timedelta
 import numpy as np
 import pandas as pd
 
@@ -452,6 +450,32 @@ def _rewrite_membership_op(self, node, left, right):
         return self.visit(node.op), node.op, left, right
 
 
+def _validate_where(w):
+    """
+    Validate that the where statement is of the right type.
+
+    The type may either be String, Expr, or list-like of Exprs.
+
+    Parameters
+    ----------
+    w : String term expression, Expr, or list-like of Exprs.
+
+    Returns
+    -------
+    where : The original where clause if the check was successful.
+
+    Raises
+    ------
+    TypeError : An invalid data type was passed in for w (e.g. dict).
+    """
+
+    if not (isinstance(w, (Expr, string_types)) or is_list_like(w)):
+        raise TypeError("where must be passed as a string, Expr, "
+                        "or list-like of Exprs")
+
+    return w
+
+
 class Expr(expr.Expr):
 
     """ hold a pytables like expression, comprised of possibly multiple 'terms'
@@ -481,11 +505,9 @@ class Expr(expr.Expr):
     "major_axis>=20130101"
     """
 
-    def __init__(self, where, op=None, value=None, queryables=None,
-                 encoding=None, scope_level=0):
+    def __init__(self, where, queryables=None, encoding=None, scope_level=0):
 
-        # try to be back compat
-        where = self.parse_back_compat(where, op, value)
+        where = _validate_where(where)
 
         self.encoding = encoding
         self.condition = None
@@ -505,7 +527,7 @@ def __init__(self, where, op=None, value=None, queryables=None,
                 if isinstance(w, Expr):
                     local_dict = w.env.scope
                 else:
-                    w = self.parse_back_compat(w)
+                    w = _validate_where(w)
                     where[idx] = w
             where = ' & ' .join(["(%s)" % w for w in where])  # noqa
 
@@ -519,59 +541,6 @@ def __init__(self, where, op=None, value=None, queryables=None,
                                         encoding=encoding)
             self.terms = self.parse()
 
-    def parse_back_compat(self, w, op=None, value=None):
-        """ allow backward compatibility for passed arguments """
-
-        if isinstance(w, dict):
-            w, op, value = w.get('field'), w.get('op'), w.get('value')
-            if not isinstance(w, string_types):
-                raise TypeError(
-                    "where must be passed as a string if op/value are passed")
-            warnings.warn("passing a dict to Expr is deprecated, "
-                          "pass the where as a single string",
-                          FutureWarning, stacklevel=10)
-        if isinstance(w, tuple):
-            if len(w) == 2:
-                w, value = w
-                op = '=='
-            elif len(w) == 3:
-                w, op, value = w
-            warnings.warn("passing a tuple into Expr is deprecated, "
-                          "pass the where as a single string",
-                          FutureWarning, stacklevel=10)
-
-        if op is not None:
-            if not isinstance(w, string_types):
-                raise TypeError(
-                    "where must be passed as a string if op/value are passed")
-
-            if isinstance(op, Expr):
-                raise TypeError("invalid op passed, must be a string")
-            w = "{0}{1}".format(w, op)
-            if value is not None:
-                if isinstance(value, Expr):
-                    raise TypeError("invalid value passed, must be a string")
-
-                # stringify with quotes these values
-                def convert(v):
-                    if isinstance(v, (datetime, np.datetime64,
-                                      timedelta, np.timedelta64)):
-                        return "'{0}'".format(v)
-                    return v
-
-                if isinstance(value, (list, tuple)):
-                    value = [convert(v) for v in value]
-                else:
-                    value = convert(value)
-
-                w = "{0}{1}".format(w, value)
-
-            warnings.warn("passing multiple values to Expr is deprecated, "
-                          "pass the where as a single string",
-                          FutureWarning, stacklevel=10)
-
-        return w
-
     def __unicode__(self):
         if self.terms is not None:
             return pprint_thing(self.terms)

pandas/tests/io/test_pytables.py

@@ -2585,59 +2585,6 @@ def test_term_compat(self):
             expected = wp.loc[:, :, ['A', 'B']]
             assert_panel_equal(result, expected)
 
-    def test_backwards_compat_without_term_object(self):
-        with ensure_clean_store(self.path) as store:
-
-            wp = Panel(np.random.randn(2, 5, 4), items=['Item1', 'Item2'],
-                       major_axis=date_range('1/1/2000', periods=5),
-                       minor_axis=['A', 'B', 'C', 'D'])
-            store.append('wp', wp)
-            with catch_warnings(record=True):
-                result = store.select('wp', [('major_axis>20000102'),
-                                             ('minor_axis', '=', ['A', 'B'])])
-            expected = wp.loc[:,
-                              wp.major_axis > Timestamp('20000102'),
-                              ['A', 'B']]
-            assert_panel_equal(result, expected)
-
-            store.remove('wp', ('major_axis>20000103'))
-            result = store.select('wp')
-            expected = wp.loc[:, wp.major_axis <= Timestamp('20000103'), :]
-            assert_panel_equal(result, expected)
-
-        with ensure_clean_store(self.path) as store:
-
-            wp = Panel(np.random.randn(2, 5, 4), items=['Item1', 'Item2'],
-                       major_axis=date_range('1/1/2000', periods=5),
-                       minor_axis=['A', 'B', 'C', 'D'])
-            store.append('wp', wp)
-
-            # stringified datetimes
-            with catch_warnings(record=True):
-                result = store.select('wp',
-                                      [('major_axis',
-                                        '>',
-                                        datetime.datetime(2000, 1, 2))])
-            expected = wp.loc[:, wp.major_axis > Timestamp('20000102')]
-            assert_panel_equal(result, expected)
-            with catch_warnings(record=True):
-                result = store.select('wp',
-                                      [('major_axis',
-                                        '>',
-                                        datetime.datetime(2000, 1, 2, 0, 0))])
-            expected = wp.loc[:, wp.major_axis > Timestamp('20000102')]
-            assert_panel_equal(result, expected)
-            with catch_warnings(record=True):
-                result = store.select('wp',
-                                      [('major_axis',
-                                        '=',
-                                        [datetime.datetime(2000, 1, 2, 0, 0),
-                                         datetime.datetime(2000, 1, 3, 0, 0)])]
-                                      )
-            expected = wp.loc[:, [Timestamp('20000102'),
-                                  Timestamp('20000103')]]
-            assert_panel_equal(result, expected)
-
     def test_same_name_scoping(self):
 
         with ensure_clean_store(self.path) as store: