DEPR: remove ix

doc/source/reference/index.rst

@@ -49,7 +49,6 @@ public functions related to data types in pandas.
 
         api/pandas.DataFrame.blocks
         api/pandas.DataFrame.as_matrix
-        api/pandas.DataFrame.ix
         api/pandas.Index.asi8
         api/pandas.Index.data
         api/pandas.Index.flags
@@ -60,7 +59,6 @@ public functions related to data types in pandas.
         api/pandas.Series.asobject
         api/pandas.Series.blocks
         api/pandas.Series.from_array
-        api/pandas.Series.ix
         api/pandas.Series.imag
         api/pandas.Series.real
 

pandas/core/indexing.py

@@ -10,10 +10,8 @@
 from pandas.util._decorators import Appender
 
 from pandas.core.dtypes.common import (
-    ensure_platform_int,
     is_float,
     is_integer,
-    is_integer_dtype,
     is_iterator,
     is_list_like,
     is_numeric_dtype,
@@ -26,15 +24,14 @@
 from pandas.core.dtypes.missing import _infer_fill_value, isna
 
 import pandas.core.common as com
-from pandas.core.index import Index, InvalidIndexError, MultiIndex
+from pandas.core.index import Index, MultiIndex
 from pandas.core.indexers import is_list_like_indexer, length_of_indexer
 
 
 # the supported indexers
 def get_indexers_list():
 
     return [
-        ("ix", _IXIndexer),
         ("iloc", _iLocIndexer),
         ("loc", _LocIndexer),
         ("at", _AtIndexer),
@@ -113,37 +110,6 @@ def __call__(self, axis=None):
         new_self.axis = axis
         return new_self
 
-    def __iter__(self):
-        raise NotImplementedError("ix is not iterable")
-
-    def __getitem__(self, key):
-        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)
-            except (KeyError, TypeError, InvalidIndexError):
-                # TypeError occurs here if the key has non-hashable entries,
-                #  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.
-                # The InvalidIndexError is only catched for compatibility
-                #  with geopandas, see
-                #  https://github.com/pandas-dev/pandas/issues/27258
-                pass
-            else:
-                if is_scalar(values):
-                    return values
-
-            return self._getitem_tuple(key)
-        else:
-            # we by definition only have the 0th axis
-            axis = self.axis or 0
-
-            key = com.apply_if_callable(key, self.obj)
-            return self._getitem_axis(key, axis=axis)
-
     def _get_label(self, label, axis: int):
         if self.ndim == 1:
             # for perf reasons we want to try _xs first
@@ -901,9 +867,6 @@ def _getitem_lowerdim(self, tup: Tuple):
         if len(tup) > self.ndim:
             raise IndexingError("Too many indexers. handle elsewhere")
 
-        # to avoid wasted computation
-        # df.ix[d1:d2, 0] -> columns first (True)
-        # df.ix[0, ['C', 'B', A']] -> rows first (False)
         for i, key in enumerate(tup):
             if is_label_like(key) or isinstance(key, tuple):
                 section = self._getitem_axis(key, axis=i)
@@ -984,41 +947,6 @@ def _getitem_nested_tuple(self, tup: Tuple):
 
         return obj
 
-    def _getitem_axis(self, key, axis: int):
-        if is_iterator(key):
-            key = list(key)
-        self._validate_key(key, axis)
-
-        labels = self.obj._get_axis(axis)
-        if isinstance(key, slice):
-            return self._get_slice_axis(key, axis=axis)
-        elif is_list_like_indexer(key) and not (
-            isinstance(key, tuple) and isinstance(labels, MultiIndex)
-        ):
-
-            if hasattr(key, "ndim") and key.ndim > 1:
-                raise ValueError("Cannot index with multidimensional key")
-
-            return self._getitem_iterable(key, axis=axis)
-        else:
-
-            # maybe coerce a float scalar to integer
-            key = labels._maybe_cast_indexer(key)
-
-            if is_integer(key):
-                if axis == 0 and isinstance(labels, MultiIndex):
-                    try:
-                        return self._get_label(key, axis=axis)
-                    except (KeyError, TypeError):
-                        if self.obj.index.levels[0].is_integer():
-                            raise
-
-                # this is the fallback! (for a non-float, non-integer index)
-                if not labels.is_floating() and not labels.is_integer():
-                    return self._get_loc(key, axis=axis)
-
-            return self._get_label(key, axis=axis)
-
     def _get_listlike_indexer(self, key, axis: int, raise_missing: bool = False):
         """
         Transform a list-like of keys into a new index and an indexer.
@@ -1275,102 +1203,6 @@ def _get_slice_axis(self, slice_obj: slice, axis: int):
         return self._slice(indexer, axis=axis, kind="iloc")
 
 
-class _IXIndexer(_NDFrameIndexer):
-    """
-    A primarily label-location based indexer, with integer position
-    fallback.
-
-    Warning: Starting in 0.20.0, the .ix indexer is deprecated, in
-    favor of the more strict .iloc and .loc indexers.
-
-    ``.ix[]`` supports mixed integer and label based access. It is
-    primarily label based, but will fall back to integer positional
-    access unless the corresponding axis is of integer type.
-
-    ``.ix`` is the most general indexer and will support any of the
-    inputs in ``.loc`` and ``.iloc``. ``.ix`` also supports floating
-    point label schemes. ``.ix`` is exceptionally useful when dealing
-    with mixed positional and label based hierarchical indexes.
-
-    However, when an axis is integer based, ONLY label based access
-    and not positional access is supported. Thus, in such cases, it's
-    usually better to be explicit and use ``.iloc`` or ``.loc``.
-
-    See more at :ref:`Advanced Indexing <advanced>`.
-    """
-
-    _ix_deprecation_warning = textwrap.dedent(
-        """
-        .ix is deprecated. Please use
-        .loc for label based indexing or
-        .iloc for positional indexing
-
-        See the documentation here:
-        http://pandas.pydata.org/pandas-docs/stable/user_guide/indexing.html#ix-indexer-is-deprecated"""  # noqa: E501
-    )
-
-    def __init__(self, name, obj):
-        warnings.warn(self._ix_deprecation_warning, FutureWarning, stacklevel=2)
-        super().__init__(name, obj)
-
-    @Appender(_NDFrameIndexer._validate_key.__doc__)
-    def _validate_key(self, key, axis: int):
-        if isinstance(key, slice):
-            return True
-
-        elif com.is_bool_indexer(key):
-            return True
-
-        elif is_list_like_indexer(key):
-            return True
-
-        else:
-
-            self._convert_scalar_indexer(key, axis)
-
-        return True
-
-    def _convert_for_reindex(self, key, axis: int):
-        """
-        Transform a list of keys into a new array ready to be used as axis of
-        the object we return (e.g. including NaNs).
-
-        Parameters
-        ----------
-        key : list-like
-            Target labels
-        axis: int
-            Where the indexing is being made
-
-        Returns
-        -------
-        list-like of labels
-        """
-        labels = self.obj._get_axis(axis)
-
-        if com.is_bool_indexer(key):
-            key = check_bool_indexer(labels, key)
-            return labels[key]
-
-        if isinstance(key, Index):
-            keyarr = labels._convert_index_indexer(key)
-        else:
-            # asarray can be unsafe, NumPy strings are weird
-            keyarr = com.asarray_tuplesafe(key)
-
-        if is_integer_dtype(keyarr):
-            # Cast the indexer to uint64 if possible so
-            # that the values returned from indexing are
-            # also uint64.
-            keyarr = labels._convert_arr_indexer(keyarr)
-
-            if not labels.is_integer():
-                keyarr = ensure_platform_int(keyarr)
-                return labels.take(keyarr)
-
-        return keyarr
-
-
 class _LocationIndexer(_NDFrameIndexer):
     _exception = Exception