Drop Python 2 support

.travis.yml

@@ -5,7 +5,6 @@ dist: xenial         # required for Python >= 3.7
 language: python
 
 python:
-    - "2.7"
     - "3.6"
     - "3.7"
 
@@ -17,20 +16,12 @@ before_install:
     # Install Miniconda
     # We do this conditionally because it saves us some downloading if the
     # version is the same.
-    - if [[ "$TRAVIS_PYTHON_VERSION" == "2.7" ]]; then
-        wget https://repo.continuum.io/miniconda/Miniconda-latest-Linux-x86_64.sh -O miniconda.sh;
-      else
-        wget https://repo.continuum.io/miniconda/Miniconda3-latest-Linux-x86_64.sh -O miniconda.sh;
-      fi
+    - wget https://repo.continuum.io/miniconda/Miniconda3-latest-Linux-x86_64.sh -O miniconda.sh;
     - bash miniconda.sh -b -p $HOME/miniconda
     - export PATH="$HOME/miniconda/bin:$PATH"
     - hash -r
     - conda config --add channels conda-forge
     - conda config --set always_yes yes --set changeps1 no
-    # workaround for conda >= 4.8
-    - if [[ "$TRAVIS_PYTHON_VERSION" == "2.7" ]]; then
-        pip install tqdm;
-      fi
     - conda update -q conda
 
     # Useful for debugging any issues with conda

README.rst

@@ -73,7 +73,7 @@ Once you have satisfied the requirements detailed below, simply run::
 Required Dependencies
 ---------------------
 
-- Python 2.7, 3.6 or 3.7
+- Python 3.6 or 3.7
 - `numpy <http://www.numpy.org/>`__ (1.13 or later)
 - `pandas <http://pandas.pydata.org/>`__ (0.20 or later)
 

condarecipe/larray/conda_build_config.yaml

@@ -1,5 +1,3 @@
 python:
-    - 2.7
-    - 3.5
     - 3.6
     - 3.7

doc/source/changes/version_0_33.rst.inc

@@ -12,7 +12,7 @@ Syntax changes
 Backward incompatible changes
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-* other backward incompatible changes
+* dropped support for Python 2 (closes :issue:`567`).
 
 
 New features

doc/source/contribute.rst

@@ -181,9 +181,6 @@ code conventions. Among others, this means:
 
 This summary should not prevent you from reading the PEP!
 
-LArray is currently compatible with both Python 2 and 3.
-So make sure your code is compatible with both versions.
-
 Step 3: Document your code
 ~~~~~~~~~~~~~~~~~~~~~~~~~~
 

larray/__init__.py

@@ -1,5 +1,3 @@
-from __future__ import absolute_import, division, print_function
-
 __version__ = '0.33-dev'
 
 

larray/core/abstractbases.py

@@ -1,18 +1,15 @@
-from __future__ import absolute_import
-
-from abc import ABCMeta
+from abc import ABC
 
 
 # define abstract base classes to enable isinstance type checking on our objects
 # idea taken from https://github.com/pandas-dev/pandas/blob/master/pandas/core/dtypes/generic.py
-# FIXME: __metaclass__ is ignored in Python 3
-class ABCAxis(object):
-    __metaclass__ = ABCMeta
+class ABCAxis(ABC):
+    pass
 
 
 class ABCAxisReference(ABCAxis):
-    __metaclass__ = ABCMeta
+    pass
 
 
-class ABCArray(object):
-    __metaclass__ = ABCMeta
+class ABCArray(ABC):
+    pass

larray/core/array.py

@@ -1,6 +1,3 @@
-# -*- coding: utf8 -*-
-from __future__ import absolute_import, division, print_function
-
 """
 Array class
 """
@@ -30,6 +27,8 @@
 
 from collections import OrderedDict
 from itertools import product, chain, groupby, islice, repeat
+from collections.abc import Iterable, Sequence
+import builtins
 import os
 import sys
 import functools
@@ -59,7 +58,6 @@
                               float_error_handler_factory, light_product, common_type,
                               renamed_to, deprecate_kwarg, LHDFStore, lazy_attribute, unique_multi, SequenceZip,
                               Repeater, Product, ensure_no_numpy_type)
-from larray.util.compat import PY2, basestring, Iterable, Sequence, builtins
 from larray.util.options import _OPTIONS, DISPLAY_MAXLINES, DISPLAY_EDGEITEMS, DISPLAY_WIDTH, DISPLAY_PRECISION
 
 
@@ -305,42 +303,23 @@ def concat(arrays, axis=0, dtype=None):
     return result
 
 
-if PY2:
-    class ArrayIterator(object):
-        __slots__ = ('next',)
-
-        def __init__(self, array):
-            data_iter = iter(array.data)
-            next_data_func = data_iter.next
-            res_axes = array.axes[1:]
-            # this case should not happen (handled by the fastpath in Array.__iter__)
-            assert len(res_axes) > 0
-
-            def next_func():
-                return Array(next_data_func(), res_axes)
+class ArrayIterator(object):
+    __slots__ = ('__next__',)
 
-            self.next = next_func
-
-        def __iter__(self):
-            return self
-else:
-    class ArrayIterator(object):
-        __slots__ = ('__next__',)
-
-        def __init__(self, array):
-            data_iter = iter(array.data)
-            next_data_func = data_iter.__next__
-            res_axes = array.axes[1:]
-            # this case should not happen (handled by the fastpath in Array.__iter__)
-            assert len(res_axes) > 0
+    def __init__(self, array):
+        data_iter = iter(array.data)
+        next_data_func = data_iter.__next__
+        res_axes = array.axes[1:]
+        # this case should not happen (handled by the fastpath in Array.__iter__)
+        assert len(res_axes) > 0
 
-            def next_func():
-                return Array(next_data_func(), res_axes)
+        def next_func():
+            return Array(next_data_func(), res_axes)
 
-            self.__next__ = next_func
+        self.__next__ = next_func
 
-        def __iter__(self):
-            return self
+    def __iter__(self):
+        return self
 
 
 # TODO: rename to ArrayIndexIndexer or something like that
@@ -826,7 +805,7 @@ def title(self):
     def title(self, title):
         import warnings
         warnings.warn("title attribute is deprecated. Please use meta.title instead", FutureWarning, stacklevel=2)
-        if not isinstance(title, basestring):
+        if not isinstance(title, str):
             raise TypeError("Expected string value, got {}".format(type(title).__name__))
         self._meta.title = title
 
@@ -1411,8 +1390,6 @@ def __array_wrap__(self, out_arr, context=None):
 
     def __bool__(self):
         return bool(self.data)
-    # Python 2
-    __nonzero__ = __bool__
 
     # TODO: either support a list (of axes names) as first argument here (and set_labels)
     #       or don't support that in set_axes
@@ -1591,7 +1568,7 @@ def reindex(self, axes_to_reindex=None, new_axis=None, fill_value=nan, inplace=F
         a1   c0   2   1
         """
         # XXX: can't we move this to AxisCollection.replace?
-        if isinstance(axes_to_reindex, basestring) and '=' in axes_to_reindex:
+        if isinstance(axes_to_reindex, str) and '=' in axes_to_reindex:
             axes_to_reindex = Axis(axes_to_reindex)
         if isinstance(axes_to_reindex, (Group, Axis)) and not isinstance(axes_to_reindex, AxisReference):
             new_axis = axes_to_reindex if isinstance(axes_to_reindex, Axis) else Axis(axes_to_reindex)
@@ -2820,7 +2797,7 @@ def to_labelgroup(key, stack_depth=1):
                 if not all(g.axis.equals(axis) for g in groups[1:]):
                     raise ValueError("group with different axes: %s" % str(key))
                 return groups
-            if isinstance(key, (Group, int, basestring, list, slice)):
+            if isinstance(key, (Group, int, str, list, slice)):
                 return self.axes._guess_axis(key)
             else:
                 raise NotImplementedError("%s has invalid type (%s) for a group aggregate key"
@@ -7744,10 +7721,10 @@ def split_axes(self, axes=None, sep='_', names=None, regex=None, sort=False, fil
         # * somehow factorize this code with AxisCollection.split_axes
         if axes is None:
             axes = {axis: None for axis in array.axes if axis.name is not None and sep in axis.name}
-        elif isinstance(axes, (int, basestring, Axis)):
+        elif isinstance(axes, (int, str, Axis)):
             axes = {axes: names}
         elif isinstance(axes, (list, tuple)):
-            if all(isinstance(axis, (int, basestring, Axis)) for axis in axes):
+            if all(isinstance(axis, (int, str, Axis)) for axis in axes):
                 axes = {axis: None for axis in axes}
             else:
                 raise ValueError("Expected tuple or list of int, string or Axis instances")
@@ -9288,12 +9265,12 @@ def stack(elements=None, axes=None, title=None, meta=None, dtype=None, res_axes=
     if elements is not None and kwargs:
         raise TypeError("stack() accepts either keyword arguments OR a collection of elements, not both")
 
-    if isinstance(axes, basestring) and '=' in axes:
+    if isinstance(axes, str) and '=' in axes:
         axes = Axis(axes)
     elif isinstance(axes, Group):
         axes = Axis(axes)
 
-    if axes is not None and not isinstance(axes, basestring):
+    if axes is not None and not isinstance(axes, str):
         axes = AxisCollection(axes)
 
     if kwargs:
@@ -9321,7 +9298,7 @@ def stack(elements=None, axes=None, title=None, meta=None, dtype=None, res_axes=
 
         if all(isinstance(e, tuple) for e in elements):
             assert all(len(e) == 2 for e in elements)
-            if axes is None or isinstance(axes, basestring):
+            if axes is None or isinstance(axes, str):
                 keys = [k for k, v in elements]
                 values = [v for k, v in elements]
                 # assert that all keys are indexers
@@ -9338,7 +9315,7 @@ def translate_and_sort_key(key, axes):
                 dict_elements = {translate_and_sort_key(key, axes): value for key, value in elements}
                 items = [(k, dict_elements[k]) for k in axes.iter_labels()]
         else:
-            if axes is None or isinstance(axes, basestring):
+            if axes is None or isinstance(axes, str):
                 axes = AxisCollection(Axis(len(elements), axes))
             else:
                 # TODO: add support for more than one axis here
@@ -9568,7 +9545,7 @@ def values_with_expand(value, axes, readonly=True, ascending=True):
         if not isinstance(axes, (tuple, list, AxisCollection)):
             axes = (axes,)
         # transform string axes definitions to objects
-        axes = [Axis(axis) if isinstance(axis, basestring) and '=' in axis else axis
+        axes = [Axis(axis) if isinstance(axis, str) and '=' in axis else axis
                 for axis in axes]
         # transform string axes references to objects
         axes = AxisCollection([axis if isinstance(axis, Axis) else all_axes[axis]