From bfd1b383e511fe914eadd97ac8678741483f4d57 Mon Sep 17 00:00:00 2001
From: jbrockmendel <jbrockmendel@gmail.com>
Date: Wed, 3 Jul 2019 18:43:09 -0700
Subject: [PATCH 01/15] implement indexers.py

---
 pandas/core/algorithms.py       |   3 +-
 pandas/core/indexers.py         | 151 ++++++++++++++++++++++++++++++++
 pandas/core/indexing.py         | 121 +------------------------
 pandas/core/internals/blocks.py |  37 ++------
 4 files changed, 160 insertions(+), 152 deletions(-)
 create mode 100644 pandas/core/indexers.py

diff --git a/pandas/core/algorithms.py b/pandas/core/algorithms.py
index 4e84d7b26b707..81f213afb6756 100644
--- a/pandas/core/algorithms.py
+++ b/pandas/core/algorithms.py
@@ -27,6 +27,7 @@
 from pandas.core.dtypes.missing import isna, na_value_for_dtype
 
 from pandas.core import common as com
+from pandas.core.indexers import validate_indices
 
 _shared_docs = {}  # type: Dict[str, str]
 
@@ -1524,8 +1525,6 @@ def take(arr, indices, axis=0, allow_fill=False, fill_value=None):
     ...      fill_value=-10)
     array([ 10,  10, -10])
     """
-    from pandas.core.indexing import validate_indices
-
     if not is_array_like(arr):
         arr = np.asarray(arr)
 
diff --git a/pandas/core/indexers.py b/pandas/core/indexers.py
new file mode 100644
index 0000000000000..f04340109c869
--- /dev/null
+++ b/pandas/core/indexers.py
@@ -0,0 +1,151 @@
+"""
+Low-dependency indexing utilities.
+"""
+import numpy as np
+
+from pandas.core.dtypes.common import is_list_like
+from pandas.core.dtypes.generic import ABCSeries, ABCIndexClass
+
+
+def is_list_like_indexer(key):
+    # allow a list_like, but exclude NamedTuples which can be indexers
+    return is_list_like(key) and not (isinstance(key, tuple) and
+                                      type(key) is not tuple)
+
+
+def length_of_indexer(indexer, target=None):
+    """
+    return the length of a single non-tuple indexer which could be a slice
+    """
+    if target is not None and isinstance(indexer, slice):
+        target_len = len(target)
+        start = indexer.start
+        stop = indexer.stop
+        step = indexer.step
+        if start is None:
+            start = 0
+        elif start < 0:
+            start += target_len
+        if stop is None or stop > target_len:
+            stop = target_len
+        elif stop < 0:
+            stop += target_len
+        if step is None:
+            step = 1
+        elif step < 0:
+            step = -step
+        return (stop - start + step - 1) // step
+    elif isinstance(indexer, (ABCSeries, ABCIndexClass, np.ndarray, list)):
+        return len(indexer)
+    elif not is_list_like_indexer(indexer):
+        return 1
+    raise AssertionError("cannot find the length of the indexer")
+
+
+def check_setitem_lengths(indexer, value, values):
+    """
+    Validate that value and indexer are the same length.
+
+    An special-case is allowed for when the indexer is a boolean array
+    and the number of true values equals the length of ``value``. In
+    this case, no exception is raised.
+
+    Parameters
+    ----------
+    indexer : sequence
+        The key for the setitem
+    value : array-like
+        The value for the setitem
+    values : array-like
+        The values being set into
+
+    Returns
+    -------
+    None
+
+    Raises
+    ------
+    ValueError
+        When the indexer is an ndarray or list and the lengths don't
+        match.
+    """
+    # boolean with truth values == len of the value is ok too
+    if isinstance(indexer, (np.ndarray, list)):
+        if is_list_like(value) and len(indexer) != len(value):
+            if not (isinstance(indexer, np.ndarray) and
+                    indexer.dtype == np.bool_ and
+                    len(indexer[indexer]) == len(value)):
+                raise ValueError("cannot set using a list-like indexer "
+                                 "with a different length than the value")
+
+    elif isinstance(indexer, slice):
+        # slice
+        if is_list_like(value) and len(values):
+            if len(value) != length_of_indexer(indexer, values):
+                raise ValueError("cannot set using a slice indexer with a "
+                                 "different length than the value")
+
+
+def is_scalar_indexer(indexer, arr_value):
+    # return True if we are all scalar indexers
+
+    if arr_value.ndim == 1:
+        if not isinstance(indexer, tuple):
+            indexer = tuple([indexer])
+            return any(isinstance(idx, np.ndarray) and len(idx) == 0
+                       for idx in indexer)
+    return False
+
+
+def is_empty_indexer(indexer, arr_value):
+    # return a boolean if we have an empty indexer
+
+    if is_list_like(indexer) and not len(indexer):
+        return True
+    if arr_value.ndim == 1:
+        if not isinstance(indexer, tuple):
+            indexer = tuple([indexer])
+        return any(isinstance(idx, np.ndarray) and len(idx) == 0
+                   for idx in indexer)
+    return False
+
+
+def validate_indices(indices, n):
+    """
+    Perform bounds-checking for an indexer.
+
+    -1 is allowed for indicating missing values.
+
+    Parameters
+    ----------
+    indices : ndarray
+    n : int
+        length of the array being indexed
+
+    Raises
+    ------
+    ValueError
+
+    Examples
+    --------
+    >>> validate_indices([1, 2], 3)
+    # OK
+    >>> validate_indices([1, -2], 3)
+    ValueError
+    >>> validate_indices([1, 2, 3], 3)
+    IndexError
+    >>> validate_indices([-1, -1], 0)
+    # OK
+    >>> validate_indices([0, 1], 0)
+    IndexError
+    """
+    if len(indices):
+        min_idx = indices.min()
+        if min_idx < -1:
+            msg = ("'indices' contains values less than allowed ({} < {})"
+                   .format(min_idx, -1))
+            raise ValueError(msg)
+
+        max_idx = indices.max()
+        if max_idx >= n:
+            raise IndexError("indices are out-of-bounds")
diff --git a/pandas/core/indexing.py b/pandas/core/indexing.py
index 677aefa15d200..b8e300c9f68ec 100755
--- a/pandas/core/indexing.py
+++ b/pandas/core/indexing.py
@@ -16,6 +16,7 @@
 
 import pandas.core.common as com
 from pandas.core.index import Index, MultiIndex
+from pandas.core.indexers import is_list_like_indexer, length_of_indexer
 
 
 # the supported indexers
@@ -2353,35 +2354,6 @@ def _convert_key(self, key, is_setter=False):
         return key
 
 
-def length_of_indexer(indexer, target=None):
-    """
-    return the length of a single non-tuple indexer which could be a slice
-    """
-    if target is not None and isinstance(indexer, slice):
-        target_len = len(target)
-        start = indexer.start
-        stop = indexer.stop
-        step = indexer.step
-        if start is None:
-            start = 0
-        elif start < 0:
-            start += target_len
-        if stop is None or stop > target_len:
-            stop = target_len
-        elif stop < 0:
-            stop += target_len
-        if step is None:
-            step = 1
-        elif step < 0:
-            step = -step
-        return (stop - start + step - 1) // step
-    elif isinstance(indexer, (ABCSeries, Index, np.ndarray, list)):
-        return len(indexer)
-    elif not is_list_like_indexer(indexer):
-        return 1
-    raise AssertionError("cannot find the length of the indexer")
-
-
 def convert_to_index_sliceable(obj, key):
     """
     if we are index sliceable, then return my slicer, otherwise return None
@@ -2458,50 +2430,6 @@ def check_bool_indexer(index: Index, key) -> np.ndarray:
     return result
 
 
-def check_setitem_lengths(indexer, value, values):
-    """
-    Validate that value and indexer are the same length.
-
-    An special-case is allowed for when the indexer is a boolean array
-    and the number of true values equals the length of ``value``. In
-    this case, no exception is raised.
-
-    Parameters
-    ----------
-    indexer : sequence
-        The key for the setitem
-    value : array-like
-        The value for the setitem
-    values : array-like
-        The values being set into
-
-    Returns
-    -------
-    None
-
-    Raises
-    ------
-    ValueError
-        When the indexer is an ndarray or list and the lengths don't
-        match.
-    """
-    # boolean with truth values == len of the value is ok too
-    if isinstance(indexer, (np.ndarray, list)):
-        if is_list_like(value) and len(indexer) != len(value):
-            if not (isinstance(indexer, np.ndarray) and
-                    indexer.dtype == np.bool_ and
-                    len(indexer[indexer]) == len(value)):
-                raise ValueError("cannot set using a list-like indexer "
-                                 "with a different length than the value")
-    # slice
-    elif isinstance(indexer, slice):
-
-        if is_list_like(value) and len(values):
-            if len(value) != length_of_indexer(indexer, values):
-                raise ValueError("cannot set using a slice indexer with a "
-                                 "different length than the value")
-
-
 def convert_missing_indexer(indexer):
     """
     reverse convert a missing indexer, which is a dict
@@ -2576,47 +2504,6 @@ def maybe_convert_indices(indices, n):
     return indices
 
 
-def validate_indices(indices, n):
-    """
-    Perform bounds-checking for an indexer.
-
-    -1 is allowed for indicating missing values.
-
-    Parameters
-    ----------
-    indices : ndarray
-    n : int
-        length of the array being indexed
-
-    Raises
-    ------
-    ValueError
-
-    Examples
-    --------
-    >>> validate_indices([1, 2], 3)
-    # OK
-    >>> validate_indices([1, -2], 3)
-    ValueError
-    >>> validate_indices([1, 2, 3], 3)
-    IndexError
-    >>> validate_indices([-1, -1], 0)
-    # OK
-    >>> validate_indices([0, 1], 0)
-    IndexError
-    """
-    if len(indices):
-        min_idx = indices.min()
-        if min_idx < -1:
-            msg = ("'indices' contains values less than allowed ({} < {})"
-                   .format(min_idx, -1))
-            raise ValueError(msg)
-
-        max_idx = indices.max()
-        if max_idx >= n:
-            raise IndexError("indices are out-of-bounds")
-
-
 def maybe_convert_ix(*args):
     """
     We likely want to take the cross-product
@@ -2646,12 +2533,6 @@ def is_nested_tuple(tup, labels):
     return False
 
 
-def is_list_like_indexer(key):
-    # allow a list_like, but exclude NamedTuples which can be indexers
-    return is_list_like(key) and not (isinstance(key, tuple) and
-                                      type(key) is not tuple)
-
-
 def is_label_like(key):
     # select a label or row
     return not isinstance(key, slice) and not is_list_like_indexer(key)
diff --git a/pandas/core/internals/blocks.py b/pandas/core/internals/blocks.py
index a9b2c0491458c..71819a9fa3089 100644
--- a/pandas/core/internals/blocks.py
+++ b/pandas/core/internals/blocks.py
@@ -36,7 +36,8 @@
     Categorical, DatetimeArray, ExtensionArray, PandasDtype, TimedeltaArray)
 from pandas.core.base import PandasObject
 import pandas.core.common as com
-from pandas.core.indexing import check_setitem_lengths
+from pandas.core.indexers import (
+    check_setitem_lengths, is_empty_indexer, is_scalar_indexer)
 from pandas.core.internals.arrays import extract_array
 import pandas.core.missing as missing
 from pandas.core.nanops import nanpercentile
@@ -854,37 +855,13 @@ def setitem(self, indexer, value):
         # length checking
         check_setitem_lengths(indexer, value, values)
 
-        def _is_scalar_indexer(indexer):
-            # return True if we are all scalar indexers
-
-            if arr_value.ndim == 1:
-                if not isinstance(indexer, tuple):
-                    indexer = tuple([indexer])
-                    return any(isinstance(idx, np.ndarray) and len(idx) == 0
-                               for idx in indexer)
-            return False
-
-        def _is_empty_indexer(indexer):
-            # return a boolean if we have an empty indexer
-
-            if is_list_like(indexer) and not len(indexer):
-                return True
-            if arr_value.ndim == 1:
-                if not isinstance(indexer, tuple):
-                    indexer = tuple([indexer])
-                return any(isinstance(idx, np.ndarray) and len(idx) == 0
-                           for idx in indexer)
-            return False
-
-        # empty indexers
-        # 8669 (empty)
-        if _is_empty_indexer(indexer):
+        if is_empty_indexer(indexer, arr_value):
+            # GH#8669 empty indexers
             pass
 
-        # setting a single element for each dim and with a rhs that could
-        # be say a list
-        # GH 6043
-        elif _is_scalar_indexer(indexer):
+        elif is_scalar_indexer(indexer):
+            # setting a single element for each dim and with a rhs that could
+            #  be e.g. a list; see GH#6043
             values[indexer] = value
 
         # if we are an exact match (ex-broadcasting),

From 746a3c005a74834a1c5b0404a5aef068512a53fb Mon Sep 17 00:00:00 2001
From: jbrockmendel <jbrockmendel@gmail.com>
Date: Wed, 3 Jul 2019 18:46:13 -0700
Subject: [PATCH 02/15] add types

---
 pandas/core/indexers.py | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/pandas/core/indexers.py b/pandas/core/indexers.py
index f04340109c869..9301a1d262da8 100644
--- a/pandas/core/indexers.py
+++ b/pandas/core/indexers.py
@@ -7,13 +7,13 @@
 from pandas.core.dtypes.generic import ABCSeries, ABCIndexClass
 
 
-def is_list_like_indexer(key):
+def is_list_like_indexer(key) -> bool:
     # allow a list_like, but exclude NamedTuples which can be indexers
     return is_list_like(key) and not (isinstance(key, tuple) and
                                       type(key) is not tuple)
 
 
-def length_of_indexer(indexer, target=None):
+def length_of_indexer(indexer, target=None) -> int:
     """
     return the length of a single non-tuple indexer which could be a slice
     """
@@ -86,7 +86,7 @@ def check_setitem_lengths(indexer, value, values):
                                  "different length than the value")
 
 
-def is_scalar_indexer(indexer, arr_value):
+def is_scalar_indexer(indexer, arr_value) -> bool:
     # return True if we are all scalar indexers
 
     if arr_value.ndim == 1:
@@ -97,7 +97,7 @@ def is_scalar_indexer(indexer, arr_value):
     return False
 
 
-def is_empty_indexer(indexer, arr_value):
+def is_empty_indexer(indexer, arr_value) -> bool:
     # return a boolean if we have an empty indexer
 
     if is_list_like(indexer) and not len(indexer):
@@ -110,7 +110,7 @@ def is_empty_indexer(indexer, arr_value):
     return False
 
 
-def validate_indices(indices, n):
+def validate_indices(indices: np.ndarray, n: int):
     """
     Perform bounds-checking for an indexer.
 

From 0233d42c8b714eec4b562429f69bf13108376a8c Mon Sep 17 00:00:00 2001
From: jbrockmendel <jbrockmendel@gmail.com>
Date: Wed, 3 Jul 2019 19:02:38 -0700
Subject: [PATCH 03/15] cleanup

---
 pandas/core/indexing.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pandas/core/indexing.py b/pandas/core/indexing.py
index b8e300c9f68ec..5bbdf15890daf 100755
--- a/pandas/core/indexing.py
+++ b/pandas/core/indexing.py
@@ -1244,7 +1244,7 @@ def _convert_to_indexer(self, obj, axis=None, is_setter=False,
                 raise
         except TypeError:
             pass
-        except (ValueError):
+        except ValueError:
             if not is_int_positional:
                 raise
 

From 35d3055a883f88acf28724e9724f54755c2b52c2 Mon Sep 17 00:00:00 2001
From: jbrockmendel <jbrockmendel@gmail.com>
Date: Wed, 3 Jul 2019 21:29:50 -0700
Subject: [PATCH 04/15] separate out helper method; add types, remove redundnat
 checks

---
 pandas/core/indexing.py                | 105 +++++++++++--------------
 pandas/core/internals/blocks.py        |   2 +-
 pandas/tests/indexing/test_indexing.py |   4 +-
 3 files changed, 47 insertions(+), 64 deletions(-)

diff --git a/pandas/core/indexing.py b/pandas/core/indexing.py
index 5bbdf15890daf..b0198295aa192 100755
--- a/pandas/core/indexing.py
+++ b/pandas/core/indexing.py
@@ -111,10 +111,12 @@ def __getitem__(self, key):
                         for x in key)
             try:
                 values = self.obj._get_value(*key)
+            except (KeyError, TypeError):
+                # TypeError is hit if key contains non-hashable entries
+                pass
+            else:
                 if is_scalar(values):
                     return values
-            except Exception:
-                pass
 
             return self._getitem_tuple(key)
         else:
@@ -537,24 +539,6 @@ def setter(item, v):
                 # reset the sliced object if unique
                 self.obj[item] = s
 
-            def can_do_equal_len():
-                """ return True if we have an equal len settable """
-                if (not len(labels) == 1 or not np.iterable(value) or
-                        is_scalar(plane_indexer[0])):
-                    return False
-
-                item = labels[0]
-                index = self.obj[item].index
-
-                values_len = len(value)
-                # equal len list/ndarray
-                if len(index) == values_len:
-                    return True
-                elif lplane_indexer == values_len:
-                    return True
-
-                return False
-
             # we need an iterable, with a ndim of at least 1
             # eg. don't pass through np.array(0)
             if is_list_like_indexer(value) and getattr(value, 'ndim', 1) > 0:
@@ -596,7 +580,8 @@ def can_do_equal_len():
                         setter(item, value[:, i].tolist())
 
                 # we have an equal len list/ndarray
-                elif can_do_equal_len():
+                elif _can_do_equal_len(labels, value, plane_indexer,
+                                       lplane_indexer, self.obj):
                     setter(labels[0], value)
 
                 # per label values
@@ -1090,7 +1075,7 @@ def _get_listlike_indexer(self, key, axis, raise_missing=False):
                                     raise_missing=raise_missing)
         return keyarr, indexer
 
-    def _getitem_iterable(self, key, axis=None):
+    def _getitem_iterable(self, key, axis: int):
         """
         Index current object with an an iterable key (which can be a boolean
         indexer, or a collection of keys).
@@ -1099,7 +1084,7 @@ def _getitem_iterable(self, key, axis=None):
         ----------
         key : iterable
             Target labels, or boolean indexer
-        axis: int, default None
+        axis: int
             Dimension on which the indexing is being made
 
         Raises
@@ -1115,10 +1100,7 @@ def _getitem_iterable(self, key, axis=None):
         -------
         scalar, DataFrame, or Series: indexed value(s),
         """
-
-        if axis is None:
-            axis = self.axis or 0
-
+        # caller is responsible for ensuring non-None axis
         self._validate_key(key, axis)
 
         labels = self.obj._get_axis(axis)
@@ -1295,20 +1277,16 @@ def _tuplify(self, loc):
         tup[0] = loc
         return tuple(tup)
 
-    def _get_slice_axis(self, slice_obj, axis=None):
+    def _get_slice_axis(self, slice_obj: slice, axis: int):
+        # caller is responsible for ensuring non-None axis
         obj = self.obj
 
-        if axis is None:
-            axis = self.axis or 0
-
         if not need_slice(slice_obj):
             return obj.copy(deep=False)
-        indexer = self._convert_slice_indexer(slice_obj, axis)
 
-        if isinstance(indexer, slice):
-            return self._slice(indexer, axis=axis, kind='iloc')
-        else:
-            return self.obj._take(indexer, axis=axis)
+        indexer = self._convert_slice_indexer(slice_obj, axis)
+        assert isinstance(indexer, slice), type(indexer)
+        return self._slice(indexer, axis=axis, kind='iloc')
 
 
 class _IXIndexer(_NDFrameIndexer):
@@ -1416,11 +1394,11 @@ def __getitem__(self, key):
         if type(key) is tuple:
             key = tuple(com.apply_if_callable(x, self.obj)
                         for x in key)
-            try:
-                if self._is_scalar_access(key):
+            if self._is_scalar_access(key):
+                try:
                     return self._getitem_scalar(key)
-            except (KeyError, IndexError, AttributeError):
-                pass
+                except (KeyError, IndexError, AttributeError):
+                    pass
             return self._getitem_tuple(key)
         else:
             # we by definition only have the 0th axis
@@ -1438,9 +1416,8 @@ def _getitem_scalar(self, key):
     def _getitem_axis(self, key, axis=None):
         raise NotImplementedError()
 
-    def _getbool_axis(self, key, axis=None):
-        if axis is None:
-            axis = self.axis or 0
+    def _getbool_axis(self, key, axis: int):
+        # caller is responsible for ensuring non-None axis
         labels = self.obj._get_axis(axis)
         key = check_bool_indexer(labels, key)
         inds, = key.nonzero()
@@ -1449,11 +1426,9 @@ def _getbool_axis(self, key, axis=None):
         except Exception as detail:
             raise self._exception(detail)
 
-    def _get_slice_axis(self, slice_obj, axis=None):
+    def _get_slice_axis(self, slice_obj: slice, axis: int):
         """ this is pretty simple as we just have to deal with labels """
-        if axis is None:
-            axis = self.axis or 0
-
+        # caller is responsible for ensuring non-None axis
         obj = self.obj
         if not need_slice(slice_obj):
             return obj.copy(deep=False)
@@ -1465,6 +1440,8 @@ def _get_slice_axis(self, slice_obj, axis=None):
         if isinstance(indexer, slice):
             return self._slice(indexer, axis=axis, kind='iloc')
         else:
+            # DatetimeIndex overrides Index.slice_indexer and may
+            #  return a DatetimeIndex instead of a slice object.
             return self.obj._take(indexer, axis=axis)
 
 
@@ -1982,6 +1959,7 @@ class _iLocIndexer(_LocationIndexer):
     _valid_types = ("integer, integer slice (START point is INCLUDED, END "
                     "point is EXCLUDED), listlike of integers, boolean array")
     _exception = IndexError
+    _get_slice_axis = _NDFrameIndexer._get_slice_axis
 
     def _validate_key(self, key, axis):
         if com.is_bool_indexer(key):
@@ -2102,20 +2080,6 @@ def _getitem_tuple(self, tup):
 
         return retval
 
-    def _get_slice_axis(self, slice_obj, axis=None):
-        if axis is None:
-            axis = self.axis or 0
-        obj = self.obj
-
-        if not need_slice(slice_obj):
-            return obj.copy(deep=False)
-
-        slice_obj = self._convert_slice_indexer(slice_obj, axis)
-        if isinstance(slice_obj, slice):
-            return self._slice(slice_obj, axis=axis, kind='iloc')
-        else:
-            return self.obj._take(slice_obj, axis=axis)
-
     def _get_list_axis(self, key, axis=None):
         """
         Return Series values by list or array of integers
@@ -2604,3 +2568,22 @@ def _maybe_numeric_slice(df, slice_, include_bool=False):
             dtypes.append(bool)
         slice_ = IndexSlice[:, df.select_dtypes(include=dtypes).columns]
     return slice_
+
+
+def _can_do_equal_len(labels, value, plane_indexer, lplane_indexer, obj):
+    """ return True if we have an equal len settable """
+    if (not len(labels) == 1 or not np.iterable(value) or
+            is_scalar(plane_indexer[0])):
+        return False
+
+    item = labels[0]
+    index = obj[item].index
+
+    values_len = len(value)
+    # equal len list/ndarray
+    if len(index) == values_len:
+        return True
+    elif lplane_indexer == values_len:
+        return True
+
+    return False
diff --git a/pandas/core/internals/blocks.py b/pandas/core/internals/blocks.py
index 71819a9fa3089..e8fc32189f928 100644
--- a/pandas/core/internals/blocks.py
+++ b/pandas/core/internals/blocks.py
@@ -859,7 +859,7 @@ def setitem(self, indexer, value):
             # GH#8669 empty indexers
             pass
 
-        elif is_scalar_indexer(indexer):
+        elif is_scalar_indexer(indexer, arr_value):
             # setting a single element for each dim and with a rhs that could
             #  be e.g. a list; see GH#6043
             values[indexer] = value
diff --git a/pandas/tests/indexing/test_indexing.py b/pandas/tests/indexing/test_indexing.py
index 92966e721aedc..c65ff2ab1d327 100644
--- a/pandas/tests/indexing/test_indexing.py
+++ b/pandas/tests/indexing/test_indexing.py
@@ -12,8 +12,8 @@
 import pandas as pd
 from pandas import DataFrame, Index, NaT, Series
 from pandas.core.generic import NDFrame
-from pandas.core.indexing import (
-    _maybe_numeric_slice, _non_reducing_slice, validate_indices)
+from pandas.core.indexers import validate_indices
+from pandas.core.indexing import _maybe_numeric_slice, _non_reducing_slice
 from pandas.tests.indexing.common import Base, _mklbl
 import pandas.util.testing as tm
 

From b1ce472c9c4807ed66d5eab30d7db4cdfeae86e0 Mon Sep 17 00:00:00 2001
From: jbrockmendel <jbrockmendel@gmail.com>
Date: Wed, 3 Jul 2019 21:35:27 -0700
Subject: [PATCH 05/15] blackify

---
 pandas/core/indexers.py         | 34 ++++++++++++++++++---------------
 pandas/core/indexing.py         |  8 ++++----
 pandas/core/internals/blocks.py |  5 ++++-
 3 files changed, 27 insertions(+), 20 deletions(-)

diff --git a/pandas/core/indexers.py b/pandas/core/indexers.py
index 9301a1d262da8..f196f4d883e12 100644
--- a/pandas/core/indexers.py
+++ b/pandas/core/indexers.py
@@ -9,8 +9,7 @@
 
 def is_list_like_indexer(key) -> bool:
     # allow a list_like, but exclude NamedTuples which can be indexers
-    return is_list_like(key) and not (isinstance(key, tuple) and
-                                      type(key) is not tuple)
+    return is_list_like(key) and not (isinstance(key, tuple) and type(key) is not tuple)
 
 
 def length_of_indexer(indexer, target=None) -> int:
@@ -72,18 +71,24 @@ def check_setitem_lengths(indexer, value, values):
     # boolean with truth values == len of the value is ok too
     if isinstance(indexer, (np.ndarray, list)):
         if is_list_like(value) and len(indexer) != len(value):
-            if not (isinstance(indexer, np.ndarray) and
-                    indexer.dtype == np.bool_ and
-                    len(indexer[indexer]) == len(value)):
-                raise ValueError("cannot set using a list-like indexer "
-                                 "with a different length than the value")
+            if not (
+                isinstance(indexer, np.ndarray)
+                and indexer.dtype == np.bool_
+                and len(indexer[indexer]) == len(value)
+            ):
+                raise ValueError(
+                    "cannot set using a list-like indexer "
+                    "with a different length than the value"
+                )
 
     elif isinstance(indexer, slice):
         # slice
         if is_list_like(value) and len(values):
             if len(value) != length_of_indexer(indexer, values):
-                raise ValueError("cannot set using a slice indexer with a "
-                                 "different length than the value")
+                raise ValueError(
+                    "cannot set using a slice indexer with a "
+                    "different length than the value"
+                )
 
 
 def is_scalar_indexer(indexer, arr_value) -> bool:
@@ -92,8 +97,7 @@ def is_scalar_indexer(indexer, arr_value) -> bool:
     if arr_value.ndim == 1:
         if not isinstance(indexer, tuple):
             indexer = tuple([indexer])
-            return any(isinstance(idx, np.ndarray) and len(idx) == 0
-                       for idx in indexer)
+            return any(isinstance(idx, np.ndarray) and len(idx) == 0 for idx in indexer)
     return False
 
 
@@ -105,8 +109,7 @@ def is_empty_indexer(indexer, arr_value) -> bool:
     if arr_value.ndim == 1:
         if not isinstance(indexer, tuple):
             indexer = tuple([indexer])
-        return any(isinstance(idx, np.ndarray) and len(idx) == 0
-                   for idx in indexer)
+        return any(isinstance(idx, np.ndarray) and len(idx) == 0 for idx in indexer)
     return False
 
 
@@ -142,8 +145,9 @@ def validate_indices(indices: np.ndarray, n: int):
     if len(indices):
         min_idx = indices.min()
         if min_idx < -1:
-            msg = ("'indices' contains values less than allowed ({} < {})"
-                   .format(min_idx, -1))
+            msg = "'indices' contains values less than allowed ({} < {})".format(
+                min_idx, -1
+            )
             raise ValueError(msg)
 
         max_idx = indices.max()
diff --git a/pandas/core/indexing.py b/pandas/core/indexing.py
index b109de6673a9a..9ad0ecbf22f8b 100755
--- a/pandas/core/indexing.py
+++ b/pandas/core/indexing.py
@@ -596,8 +596,9 @@ def setter(item, v):
                         setter(item, value[:, i].tolist())
 
                 # we have an equal len list/ndarray
-                elif _can_do_equal_len(labels, value, plane_indexer,
-                                       lplane_indexer, self.obj):
+                elif _can_do_equal_len(
+                    labels, value, plane_indexer, lplane_indexer, self.obj
+                ):
                     setter(labels[0], value)
 
                 # per label values
@@ -2626,8 +2627,7 @@ def _maybe_numeric_slice(df, slice_, include_bool=False):
 
 def _can_do_equal_len(labels, value, plane_indexer, lplane_indexer, obj):
     """ return True if we have an equal len settable """
-    if (not len(labels) == 1 or not np.iterable(value) or
-            is_scalar(plane_indexer[0])):
+    if not len(labels) == 1 or not np.iterable(value) or is_scalar(plane_indexer[0]):
         return False
 
     item = labels[0]
diff --git a/pandas/core/internals/blocks.py b/pandas/core/internals/blocks.py
index 3704201ca4749..9d9a019a7158c 100644
--- a/pandas/core/internals/blocks.py
+++ b/pandas/core/internals/blocks.py
@@ -73,7 +73,10 @@
 from pandas.core.base import PandasObject
 import pandas.core.common as com
 from pandas.core.indexers import (
-    check_setitem_lengths, is_empty_indexer, is_scalar_indexer)
+    check_setitem_lengths,
+    is_empty_indexer,
+    is_scalar_indexer,
+)
 from pandas.core.internals.arrays import extract_array
 import pandas.core.missing as missing
 from pandas.core.nanops import nanpercentile

From b2a101aea86dd75d60a02175edf9d644879ec4fb Mon Sep 17 00:00:00 2001
From: jbrockmendel <jbrockmendel@gmail.com>
Date: Thu, 4 Jul 2019 07:15:49 -0700
Subject: [PATCH 06/15] types

---
 pandas/core/indexers.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/pandas/core/indexers.py b/pandas/core/indexers.py
index f196f4d883e12..7027a733ae8fb 100644
--- a/pandas/core/indexers.py
+++ b/pandas/core/indexers.py
@@ -41,7 +41,7 @@ def length_of_indexer(indexer, target=None) -> int:
     raise AssertionError("cannot find the length of the indexer")
 
 
-def check_setitem_lengths(indexer, value, values):
+def check_setitem_lengths(indexer, value, values) -> None:
     """
     Validate that value and indexer are the same length.
 
@@ -113,7 +113,7 @@ def is_empty_indexer(indexer, arr_value) -> bool:
     return False
 
 
-def validate_indices(indices: np.ndarray, n: int):
+def validate_indices(indices: np.ndarray, n: int) -> None:
     """
     Perform bounds-checking for an indexer.
 

From 51ceb24c5b03da71d86d49ee930ed49b4a21d9f1 Mon Sep 17 00:00:00 2001
From: jbrockmendel <jbrockmendel@gmail.com>
Date: Thu, 4 Jul 2019 07:21:52 -0700
Subject: [PATCH 07/15] move indexers

---
 pandas/core/indexers.py           | 46 ++++++++++++++++++++++++++++++-
 pandas/core/indexes/base.py       |  2 +-
 pandas/core/indexing.py           | 44 -----------------------------
 pandas/core/internals/managers.py |  2 +-
 pandas/core/series.py             |  3 +-
 5 files changed, 49 insertions(+), 48 deletions(-)

diff --git a/pandas/core/indexers.py b/pandas/core/indexers.py
index 7027a733ae8fb..d4e9f2680e68f 100644
--- a/pandas/core/indexers.py
+++ b/pandas/core/indexers.py
@@ -4,7 +4,7 @@
 import numpy as np
 
 from pandas.core.dtypes.common import is_list_like
-from pandas.core.dtypes.generic import ABCSeries, ABCIndexClass
+from pandas.core.dtypes.generic import ABCIndexClass, ABCSeries
 
 
 def is_list_like_indexer(key) -> bool:
@@ -153,3 +153,47 @@ def validate_indices(indices: np.ndarray, n: int) -> None:
         max_idx = indices.max()
         if max_idx >= n:
             raise IndexError("indices are out-of-bounds")
+
+
+def maybe_convert_indices(indices, n: int):
+    """
+    Attempt to convert indices into valid, positive indices.
+
+    If we have negative indices, translate to positive here.
+    If we have indices that are out-of-bounds, raise an IndexError.
+
+    Parameters
+    ----------
+    indices : array-like
+        The array of indices that we are to convert.
+    n : int
+        The number of elements in the array that we are indexing.
+
+    Returns
+    -------
+    valid_indices : array-like
+        An array-like of positive indices that correspond to the ones
+        that were passed in initially to this function.
+
+    Raises
+    ------
+    IndexError : one of the converted indices either exceeded the number
+        of elements (specified by `n`) OR was still negative.
+    """
+
+    if isinstance(indices, list):
+        indices = np.array(indices)
+        if len(indices) == 0:
+            # If list is empty, np.array will return float and cause indexing
+            # errors.
+            return np.empty(0, dtype=np.intp)
+
+    mask = indices < 0
+    if mask.any():
+        indices = indices.copy()
+        indices[mask] += n
+
+    mask = (indices >= n) | (indices < 0)
+    if mask.any():
+        raise IndexError("indices are out-of-bounds")
+    return indices
diff --git a/pandas/core/indexes/base.py b/pandas/core/indexes/base.py
index 973a022cfc3f1..34a0acc711e5f 100644
--- a/pandas/core/indexes/base.py
+++ b/pandas/core/indexes/base.py
@@ -66,6 +66,7 @@
 from pandas.core.arrays import ExtensionArray
 from pandas.core.base import IndexOpsMixin, PandasObject
 import pandas.core.common as com
+from pandas.core.indexers import maybe_convert_indices
 from pandas.core.indexes.frozen import FrozenList
 import pandas.core.missing as missing
 from pandas.core.ops import get_op_result_name, make_invalid_op
@@ -3317,7 +3318,6 @@ def _convert_list_indexer(self, keyarr, kind=None):
                 # values outside the range of indices so as to trigger an
                 # IndexError in maybe_convert_indices
                 indexer[indexer < 0] = len(self)
-                from pandas.core.indexing import maybe_convert_indices
 
                 return maybe_convert_indices(indexer, len(self))
 
diff --git a/pandas/core/indexing.py b/pandas/core/indexing.py
index 9ad0ecbf22f8b..1753d24d23f5c 100755
--- a/pandas/core/indexing.py
+++ b/pandas/core/indexing.py
@@ -2475,50 +2475,6 @@ def get_indexer(_i, _idx):
     return tuple(get_indexer(_i, _idx) for _i, _idx in enumerate(indexer))
 
 
-def maybe_convert_indices(indices, n):
-    """
-    Attempt to convert indices into valid, positive indices.
-
-    If we have negative indices, translate to positive here.
-    If we have indices that are out-of-bounds, raise an IndexError.
-
-    Parameters
-    ----------
-    indices : array-like
-        The array of indices that we are to convert.
-    n : int
-        The number of elements in the array that we are indexing.
-
-    Returns
-    -------
-    valid_indices : array-like
-        An array-like of positive indices that correspond to the ones
-        that were passed in initially to this function.
-
-    Raises
-    ------
-    IndexError : one of the converted indices either exceeded the number
-        of elements (specified by `n`) OR was still negative.
-    """
-
-    if isinstance(indices, list):
-        indices = np.array(indices)
-        if len(indices) == 0:
-            # If list is empty, np.array will return float and cause indexing
-            # errors.
-            return np.empty(0, dtype=np.intp)
-
-    mask = indices < 0
-    if mask.any():
-        indices = indices.copy()
-        indices[mask] += n
-
-    mask = (indices >= n) | (indices < 0)
-    if mask.any():
-        raise IndexError("indices are out-of-bounds")
-    return indices
-
-
 def maybe_convert_ix(*args):
     """
     We likely want to take the cross-product
diff --git a/pandas/core/internals/managers.py b/pandas/core/internals/managers.py
index c5254aaa4af5f..4bf43056f172d 100644
--- a/pandas/core/internals/managers.py
+++ b/pandas/core/internals/managers.py
@@ -34,7 +34,7 @@
 import pandas.core.algorithms as algos
 from pandas.core.base import PandasObject
 from pandas.core.index import Index, MultiIndex, ensure_index
-from pandas.core.indexing import maybe_convert_indices
+from pandas.core.indexers import maybe_convert_indices
 
 from pandas.io.formats.printing import pprint_thing
 
diff --git a/pandas/core/series.py b/pandas/core/series.py
index b3a7f38aef8ef..1943b66818b95 100644
--- a/pandas/core/series.py
+++ b/pandas/core/series.py
@@ -66,12 +66,13 @@
     MultiIndex,
     ensure_index,
 )
+from pandas.core.indexers import maybe_convert_indices
 from pandas.core.indexes.accessors import CombinedDatetimelikeProperties
 import pandas.core.indexes.base as ibase
 from pandas.core.indexes.datetimes import DatetimeIndex
 from pandas.core.indexes.period import PeriodIndex
 from pandas.core.indexes.timedeltas import TimedeltaIndex
-from pandas.core.indexing import check_bool_indexer, maybe_convert_indices
+from pandas.core.indexing import check_bool_indexer
 from pandas.core.internals import SingleBlockManager
 from pandas.core.internals.construction import sanitize_array
 from pandas.core.strings import StringMethods

From 7efe2d1bea8590c02a5794a2dd0750521bfee302 Mon Sep 17 00:00:00 2001
From: jbrockmendel <jbrockmendel@gmail.com>
Date: Thu, 4 Jul 2019 07:24:59 -0700
Subject: [PATCH 08/15] organize file

---
 pandas/core/indexers.py | 110 ++++++++++++++++++++++------------------
 1 file changed, 61 insertions(+), 49 deletions(-)

diff --git a/pandas/core/indexers.py b/pandas/core/indexers.py
index d4e9f2680e68f..794869e6ac85a 100644
--- a/pandas/core/indexers.py
+++ b/pandas/core/indexers.py
@@ -7,39 +7,38 @@
 from pandas.core.dtypes.generic import ABCIndexClass, ABCSeries
 
 
+# -----------------------------------------------------------
+# Indexer Identification
+
 def is_list_like_indexer(key) -> bool:
     # allow a list_like, but exclude NamedTuples which can be indexers
     return is_list_like(key) and not (isinstance(key, tuple) and type(key) is not tuple)
 
 
-def length_of_indexer(indexer, target=None) -> int:
-    """
-    return the length of a single non-tuple indexer which could be a slice
-    """
-    if target is not None and isinstance(indexer, slice):
-        target_len = len(target)
-        start = indexer.start
-        stop = indexer.stop
-        step = indexer.step
-        if start is None:
-            start = 0
-        elif start < 0:
-            start += target_len
-        if stop is None or stop > target_len:
-            stop = target_len
-        elif stop < 0:
-            stop += target_len
-        if step is None:
-            step = 1
-        elif step < 0:
-            step = -step
-        return (stop - start + step - 1) // step
-    elif isinstance(indexer, (ABCSeries, ABCIndexClass, np.ndarray, list)):
-        return len(indexer)
-    elif not is_list_like_indexer(indexer):
-        return 1
-    raise AssertionError("cannot find the length of the indexer")
+def is_scalar_indexer(indexer, arr_value) -> bool:
+    # return True if we are all scalar indexers
 
+    if arr_value.ndim == 1:
+        if not isinstance(indexer, tuple):
+            indexer = tuple([indexer])
+            return any(isinstance(idx, np.ndarray) and len(idx) == 0 for idx in indexer)
+    return False
+
+
+def is_empty_indexer(indexer, arr_value) -> bool:
+    # return a boolean if we have an empty indexer
+
+    if is_list_like(indexer) and not len(indexer):
+        return True
+    if arr_value.ndim == 1:
+        if not isinstance(indexer, tuple):
+            indexer = tuple([indexer])
+        return any(isinstance(idx, np.ndarray) and len(idx) == 0 for idx in indexer)
+    return False
+
+
+# -----------------------------------------------------------
+# Indexer Validation
 
 def check_setitem_lengths(indexer, value, values) -> None:
     """
@@ -91,28 +90,6 @@ def check_setitem_lengths(indexer, value, values) -> None:
                 )
 
 
-def is_scalar_indexer(indexer, arr_value) -> bool:
-    # return True if we are all scalar indexers
-
-    if arr_value.ndim == 1:
-        if not isinstance(indexer, tuple):
-            indexer = tuple([indexer])
-            return any(isinstance(idx, np.ndarray) and len(idx) == 0 for idx in indexer)
-    return False
-
-
-def is_empty_indexer(indexer, arr_value) -> bool:
-    # return a boolean if we have an empty indexer
-
-    if is_list_like(indexer) and not len(indexer):
-        return True
-    if arr_value.ndim == 1:
-        if not isinstance(indexer, tuple):
-            indexer = tuple([indexer])
-        return any(isinstance(idx, np.ndarray) and len(idx) == 0 for idx in indexer)
-    return False
-
-
 def validate_indices(indices: np.ndarray, n: int) -> None:
     """
     Perform bounds-checking for an indexer.
@@ -155,6 +132,9 @@ def validate_indices(indices: np.ndarray, n: int) -> None:
             raise IndexError("indices are out-of-bounds")
 
 
+# -----------------------------------------------------------
+# Indexer Conversion
+
 def maybe_convert_indices(indices, n: int):
     """
     Attempt to convert indices into valid, positive indices.
@@ -197,3 +177,35 @@ def maybe_convert_indices(indices, n: int):
     if mask.any():
         raise IndexError("indices are out-of-bounds")
     return indices
+
+
+# -----------------------------------------------------------
+# Unsorted
+
+def length_of_indexer(indexer, target=None) -> int:
+    """
+    return the length of a single non-tuple indexer which could be a slice
+    """
+    if target is not None and isinstance(indexer, slice):
+        target_len = len(target)
+        start = indexer.start
+        stop = indexer.stop
+        step = indexer.step
+        if start is None:
+            start = 0
+        elif start < 0:
+            start += target_len
+        if stop is None or stop > target_len:
+            stop = target_len
+        elif stop < 0:
+            stop += target_len
+        if step is None:
+            step = 1
+        elif step < 0:
+            step = -step
+        return (stop - start + step - 1) // step
+    elif isinstance(indexer, (ABCSeries, ABCIndexClass, np.ndarray, list)):
+        return len(indexer)
+    elif not is_list_like_indexer(indexer):
+        return 1
+    raise AssertionError("cannot find the length of the indexer")

From 3322f4e85ea66b90f6ddb901dca0b1d73f5e7002 Mon Sep 17 00:00:00 2001
From: jbrockmendel <jbrockmendel@gmail.com>
Date: Sat, 6 Jul 2019 07:31:12 -0700
Subject: [PATCH 09/15] isort

---
 pandas/core/indexers.py | 1 -
 1 file changed, 1 deletion(-)

diff --git a/pandas/core/indexers.py b/pandas/core/indexers.py
index 794869e6ac85a..81dc914deea49 100644
--- a/pandas/core/indexers.py
+++ b/pandas/core/indexers.py
@@ -6,7 +6,6 @@
 from pandas.core.dtypes.common import is_list_like
 from pandas.core.dtypes.generic import ABCIndexClass, ABCSeries
 
-
 # -----------------------------------------------------------
 # Indexer Identification
 

From 5b6335b689e68895905321794ea3feea40467fc9 Mon Sep 17 00:00:00 2001
From: jbrockmendel <jbrockmendel@gmail.com>
Date: Sat, 6 Jul 2019 07:34:26 -0700
Subject: [PATCH 10/15] lint+isort compat

---
 pandas/core/indexers.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/pandas/core/indexers.py b/pandas/core/indexers.py
index 81dc914deea49..445c72675c3ac 100644
--- a/pandas/core/indexers.py
+++ b/pandas/core/indexers.py
@@ -9,6 +9,7 @@
 # -----------------------------------------------------------
 # Indexer Identification
 
+
 def is_list_like_indexer(key) -> bool:
     # allow a list_like, but exclude NamedTuples which can be indexers
     return is_list_like(key) and not (isinstance(key, tuple) and type(key) is not tuple)

From 74c3d36a0164190a6bce8f0034005d9d6ac44d1f Mon Sep 17 00:00:00 2001
From: jbrockmendel <jbrockmendel@gmail.com>
Date: Sun, 7 Jul 2019 15:08:47 -0700
Subject: [PATCH 11/15] blackify

---
 pandas/core/indexers.py | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/pandas/core/indexers.py b/pandas/core/indexers.py
index 445c72675c3ac..d4b2c5b917997 100644
--- a/pandas/core/indexers.py
+++ b/pandas/core/indexers.py
@@ -40,6 +40,7 @@ def is_empty_indexer(indexer, arr_value) -> bool:
 # -----------------------------------------------------------
 # Indexer Validation
 
+
 def check_setitem_lengths(indexer, value, values) -> None:
     """
     Validate that value and indexer are the same length.
@@ -135,6 +136,7 @@ def validate_indices(indices: np.ndarray, n: int) -> None:
 # -----------------------------------------------------------
 # Indexer Conversion
 
+
 def maybe_convert_indices(indices, n: int):
     """
     Attempt to convert indices into valid, positive indices.
@@ -182,6 +184,7 @@ def maybe_convert_indices(indices, n: int):
 # -----------------------------------------------------------
 # Unsorted
 
+
 def length_of_indexer(indexer, target=None) -> int:
     """
     return the length of a single non-tuple indexer which could be a slice

From 0fafcc430b2d1348389b74ab31b40c2c7e6ffe7f Mon Sep 17 00:00:00 2001
From: jbrockmendel <jbrockmendel@gmail.com>
Date: Sun, 7 Jul 2019 19:44:12 -0700
Subject: [PATCH 12/15] remove assertion

---
 pandas/core/indexing.py | 1 -
 1 file changed, 1 deletion(-)

diff --git a/pandas/core/indexing.py b/pandas/core/indexing.py
index f697ec7b54efa..429d9f166b294 100755
--- a/pandas/core/indexing.py
+++ b/pandas/core/indexing.py
@@ -1316,7 +1316,6 @@ def _get_slice_axis(self, slice_obj: slice, axis: int):
             return obj.copy(deep=False)
 
         indexer = self._convert_slice_indexer(slice_obj, axis)
-        assert isinstance(indexer, slice), type(indexer)
         return self._slice(indexer, axis=axis, kind="iloc")
 
 

From 8b8442c618f9793ab7d4ab226917529573898c05 Mon Sep 17 00:00:00 2001
From: jbrockmendel <jbrockmendel@gmail.com>
Date: Sun, 7 Jul 2019 19:45:28 -0700
Subject: [PATCH 13/15] add comment for GH#27259

---
 pandas/core/indexing.py | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/pandas/core/indexing.py b/pandas/core/indexing.py
index 429d9f166b294..ae066a41d1474 100755
--- a/pandas/core/indexing.py
+++ b/pandas/core/indexing.py
@@ -115,7 +115,7 @@ def __iter__(self):
         raise NotImplementedError("ix is not iterable")
 
     def __getitem__(self, key):
-        if type(key) is tuple:
+        if isinstance(key, tuple):
             key = tuple(com.apply_if_callable(x, self.obj) for x in key)
             try:
                 values = self.obj._get_value(*key)
@@ -124,6 +124,8 @@ def __getitem__(self, key):
                 #  generally slice or list.
                 # TODO(ix): most/all of the TypeError cases here are for ix,
                 #  so this check can be removed once ix is removed.
+                # Note: InvalidIndexError is here for geopandas compat,
+                #  see GH#27259
                 pass
             else:
                 if is_scalar(values):
@@ -1422,7 +1424,7 @@ class _LocationIndexer(_NDFrameIndexer):
     _exception = Exception
 
     def __getitem__(self, key):
-        if type(key) is tuple:
+        if isinstance(key, tuple):
             key = tuple(com.apply_if_callable(x, self.obj) for x in key)
             if self._is_scalar_access(key):
                 try:

From d4780373e386d9b7dccef6108e8c2ec606d02017 Mon Sep 17 00:00:00 2001
From: jbrockmendel <jbrockmendel@gmail.com>
Date: Sun, 7 Jul 2019 19:50:23 -0700
Subject: [PATCH 14/15] docstring

---
 pandas/core/indexers.py | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/pandas/core/indexers.py b/pandas/core/indexers.py
index d4b2c5b917997..7b0030b91e4dc 100644
--- a/pandas/core/indexers.py
+++ b/pandas/core/indexers.py
@@ -11,6 +11,17 @@
 
 
 def is_list_like_indexer(key) -> bool:
+    """
+    Check if we have a list-like indexer that is *not* a NamedTuple.
+
+    Parameters
+    ----------
+    key : object
+
+    Returns
+    -------
+    bool
+    """
     # allow a list_like, but exclude NamedTuples which can be indexers
     return is_list_like(key) and not (isinstance(key, tuple) and type(key) is not tuple)
 

From 39fa0141fb2a695fb47bac4a4895e3c6c8de41f5 Mon Sep 17 00:00:00 2001
From: jbrockmendel <jbrockmendel@gmail.com>
Date: Mon, 8 Jul 2019 06:51:00 -0700
Subject: [PATCH 15/15] revert isinstance to type checks

---
 pandas/core/indexing.py | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/pandas/core/indexing.py b/pandas/core/indexing.py
index ef9d44e7787f9..f132e4ddbd0c0 100755
--- a/pandas/core/indexing.py
+++ b/pandas/core/indexing.py
@@ -115,7 +115,9 @@ def __iter__(self):
         raise NotImplementedError("ix is not iterable")
 
     def __getitem__(self, key):
-        if isinstance(key, tuple):
+        if type(key) is tuple:
+            # Note: we check the type exactly instead of with isinstance
+            #  because NamedTuple is checked separately.
             key = tuple(com.apply_if_callable(x, self.obj) for x in key)
             try:
                 values = self.obj._get_value(*key)
@@ -1425,7 +1427,7 @@ class _LocationIndexer(_NDFrameIndexer):
     _exception = Exception
 
     def __getitem__(self, key):
-        if isinstance(key, tuple):
+        if type(key) is tuple:
             key = tuple(com.apply_if_callable(x, self.obj) for x in key)
             if self._is_scalar_access(key):
                 try: