revert try_cast_results

pandas/core/internals/__init__.py

@@ -1,6 +1,5 @@
 # -*- coding: utf-8 -*-
 from .blocks import (  # noqa:F401
-    try_cast_result,  # frame
     _block2d_to_blocknd, _factor_indexer, _block_shape,  # io.pytables
     _safe_reshape,  # io.packers
     make_block,     # io.pytables, io.packers

pandas/core/internals/blocks.py

@@ -74,55 +74,6 @@
 from pandas.io.formats.printing import pprint_thing
 
 
-def try_cast_result(left, result, dtype=None):
-    """
-    Try to cast the result to the original dtype for `left`; we may have
-    roundtripped thru object in the mean-time.
-
-    Parameters
-    ----------
-    left : array-like
-    result : array-like
-    dtype : np.dtype, pd.dtype, or None (default None)
-
-    Returns
-    -------
-    maybe_casted : same type as `result`
-    """
-    if dtype is None:
-        dtype = left.dtype
-
-    if (is_integer_dtype(left) or is_bool_dtype(left) or
-            is_datetime64_dtype(left) or is_datetime64tz_dtype(left)):
-        pass
-    elif is_object_dtype(left) and lib.infer_dtype(left) == 'boolean':
-        # disguised is_bool_dtype
-        pass
-    elif is_float_dtype(left) and result.dtype == left.dtype:
-
-        # protect against a bool/object showing up here
-        if isinstance(dtype, compat.string_types) and dtype == 'infer':
-            return result
-        if not isinstance(dtype, type):
-            dtype = dtype.type
-        if issubclass(dtype, (np.bool_, np.object_)):
-            if issubclass(dtype, np.bool_):
-                if isna(result).all():
-                    return result.astype(np.bool_)
-                else:
-                    result = result.astype(np.object_)
-                    result[result == 1] = True
-                    result[result == 0] = False
-                    return result
-            else:
-                return result.astype(np.object_)
-
-        return result
-
-    # may need to change the dtype here
-    return maybe_downcast_to_dtype(result, dtype)
-
-
 class Block(PandasObject):
     """
     Canonical n-dimensional unit of homogeneous dtype contained in a pandas
@@ -748,7 +699,34 @@ def _try_cast_result(self, result, dtype=None):
         """ try to cast the result to our original type, we may have
         roundtripped thru object in the mean-time
         """
-        return try_cast_result(self, result, dtype)
+        if dtype is None:
+            dtype = self.dtype
+
+        if self.is_integer or self.is_bool or self.is_datetime:
+            pass
+        elif self.is_float and result.dtype == self.dtype:
+
+            # protect against a bool/object showing up here
+            if isinstance(dtype, compat.string_types) and dtype == 'infer':
+                return result
+            if not isinstance(dtype, type):
+                dtype = dtype.type
+            if issubclass(dtype, (np.bool_, np.object_)):
+                if issubclass(dtype, np.bool_):
+                    if isna(result).all():
+                        return result.astype(np.bool_)
+                    else:
+                        result = result.astype(np.object_)
+                        result[result == 1] = True
+                        result[result == 0] = False
+                        return result
+                else:
+                    return result.astype(np.object_)
+
+            return result
+
+        # may need to change the dtype here
+        return maybe_downcast_to_dtype(result, dtype)
 
     def _try_coerce_args(self, values, other):
         """ provide coercion to our input arguments """