MAINT: cleanup unused imports; avoid redefinition of imports

* Cleanup unused imports (F401) of mostly standard Python modules,
  or some internal but unlikely referenced modules
* Where internal imports are potentially used, mark with noqa
* Avoid redefinition of imports (F811)

32 files changed, 24 insertions, 51 deletions

diff --git a/numpy/core/_type_aliases.py b/numpy/core/_type_aliases.py
index dfb70430f..c26431443 100644
--- a/numpy/core/_type_aliases.py
+++ b/numpy/core/_type_aliases.py
@@ -23,7 +23,6 @@ and sometimes other mappings too.
 
 """
 import warnings
-import sys
 
 from numpy.compat import unicode
 from numpy._globals import VisibleDeprecationWarning
diff --git a/numpy/core/code_generators/generate_ufunc_api.py b/numpy/core/code_generators/generate_ufunc_api.py
index c32cf3e44..04c023675 100644
--- a/numpy/core/code_generators/generate_ufunc_api.py
+++ b/numpy/core/code_generators/generate_ufunc_api.py
@@ -3,8 +3,7 @@ import genapi
 
 import numpy_api
 
-from genapi import \
-        TypeApi, GlobalVarApi, FunctionApi, BoolValuesApi
+from genapi import TypeApi, FunctionApi
 
 h_template = r"""
 #ifdef _UMATHMODULE
diff --git a/numpy/core/function_base.py b/numpy/core/function_base.py
index 8f92a4f71..6d49b9055 100644
--- a/numpy/core/function_base.py
+++ b/numpy/core/function_base.py
@@ -4,8 +4,7 @@ import operator
 import types
 
 from . import numeric as _nx
-from .numeric import (result_type, NaN, shares_memory, MAY_SHARE_BOUNDS,
-                      TooHardError, asanyarray, ndim)
+from .numeric import result_type, NaN, asanyarray, ndim
 from numpy.core.multiarray import add_docstring
 from numpy.core import overrides
 
diff --git a/numpy/core/setup.py b/numpy/core/setup.py
index 66c1b782e..ec96467c6 100644
--- a/numpy/core/setup.py
+++ b/numpy/core/setup.py
@@ -392,7 +392,7 @@ def visibility_define(config):
 
 def configuration(parent_package='',top_path=None):
     from numpy.distutils.misc_util import Configuration, dot_join
-    from numpy.distutils.system_info import get_info, dict_append
+    from numpy.distutils.system_info import get_info
 
     config = Configuration('core', parent_package, top_path)
     local_dir = config.local_path
diff --git a/numpy/core/umath.py b/numpy/core/umath.py
index c3cebb03f..d2f769505 100644
--- a/numpy/core/umath.py
+++ b/numpy/core/umath.py
@@ -8,9 +8,7 @@ by importing from the extension module.
 
 from . import _multiarray_umath
 from ._multiarray_umath import *  # noqa: F403
-from ._multiarray_umath import (
-    _UFUNC_API, _add_newdoc_ufunc, _ones_like
-    )
+from ._multiarray_umath import _UFUNC_API, _add_newdoc_ufunc
 
 __all__ = [
     '_UFUNC_API', 'ERR_CALL', 'ERR_DEFAULT', 'ERR_IGNORE', 'ERR_LOG',
diff --git a/numpy/distutils/command/build_clib.py b/numpy/distutils/command/build_clib.py
index 1b4666888..d679b2d03 100644
--- a/numpy/distutils/command/build_clib.py
+++ b/numpy/distutils/command/build_clib.py
@@ -9,9 +9,10 @@ from distutils.errors import DistutilsSetupError, DistutilsError, \
 
 from numpy.distutils import log
 from distutils.dep_util import newer_group
-from numpy.distutils.misc_util import filter_sources, has_f_sources,\
-     has_cxx_sources, all_strings, get_lib_source_files, is_sequence, \
-     get_numpy_include_dirs
+from numpy.distutils.misc_util import (
+    filter_sources, get_lib_source_files, get_numpy_include_dirs,
+    has_cxx_sources, has_f_sources, is_sequence
+)
 
 # Fix Python distutils bug sf #1718574:
 _l = old_build_clib.user_options
diff --git a/numpy/distutils/command/build_ext.py b/numpy/distutils/command/build_ext.py
index a0da83ff4..0e07ba9cf 100644
--- a/numpy/distutils/command/build_ext.py
+++ b/numpy/distutils/command/build_ext.py
@@ -13,11 +13,11 @@ from distutils.file_util import copy_file
 
 from numpy.distutils import log
 from numpy.distutils.exec_command import filepath_from_subprocess_output
-from numpy.distutils.system_info import combine_paths, system_info
-from numpy.distutils.misc_util import filter_sources, has_f_sources, \
-    has_cxx_sources, get_ext_source_files, \
-    get_numpy_include_dirs, is_sequence, get_build_architecture, \
-    msvc_version
+from numpy.distutils.system_info import combine_paths
+from numpy.distutils.misc_util import (
+    filter_sources, get_ext_source_files, get_numpy_include_dirs,
+    has_cxx_sources, has_f_sources, is_sequence
+)
 from numpy.distutils.command.config_compiler import show_fortran_compilers
 
 
diff --git a/numpy/distutils/core.py b/numpy/distutils/core.py
index d3461aa49..d5551f349 100644
--- a/numpy/distutils/core.py
+++ b/numpy/distutils/core.py
@@ -1,5 +1,5 @@
 import sys
-from distutils.core import Distribution, setup
+from distutils.core import Distribution
 
 if 'setuptools' in sys.modules:
     have_setuptools = True
@@ -25,7 +25,7 @@ from numpy.distutils.command import config, config_compiler, \
      build, build_py, build_ext, build_clib, build_src, build_scripts, \
      sdist, install_data, install_headers, install, bdist_rpm, \
      install_clib
-from numpy.distutils.misc_util import get_data_files, is_sequence, is_string
+from numpy.distutils.misc_util import is_sequence, is_string
 
 numpy_cmdclass = {'build':            build.build,
                   'build_src':        build_src.build_src,
diff --git a/numpy/distutils/extension.py b/numpy/distutils/extension.py
index 704f1e7aa..67114ef2e 100644
--- a/numpy/distutils/extension.py
+++ b/numpy/distutils/extension.py
@@ -6,7 +6,6 @@ modules in setup scripts.
 Overridden to support f2py.
 
 """
-import sys
 import re
 from distutils.extension import Extension as old_Extension
 
diff --git a/numpy/distutils/fcompiler/__init__.py b/numpy/distutils/fcompiler/__init__.py
index a88b0d713..1c3069363 100644
--- a/numpy/distutils/fcompiler/__init__.py
+++ b/numpy/distutils/fcompiler/__init__.py
@@ -19,7 +19,6 @@ __all__ = ['FCompiler', 'new_fcompiler', 'show_fcompilers',
 import os
 import sys
 import re
-import types
 
 from numpy.compat import open_latin1
 
diff --git a/numpy/distutils/fcompiler/environment.py b/numpy/distutils/fcompiler/environment.py
index ae5fc404a..21a5be003 100644
--- a/numpy/distutils/fcompiler/environment.py
+++ b/numpy/distutils/fcompiler/environment.py
@@ -1,5 +1,4 @@
 import os
-import warnings
 from distutils.dist import Distribution
 
 __metaclass__ = type
diff --git a/numpy/distutils/fcompiler/gnu.py b/numpy/distutils/fcompiler/gnu.py
index 128e54db3..8d69f6ba6 100644
--- a/numpy/distutils/fcompiler/gnu.py
+++ b/numpy/distutils/fcompiler/gnu.py
@@ -10,7 +10,6 @@ import subprocess
 from subprocess import Popen, PIPE, STDOUT
 from numpy.distutils.exec_command import filepath_from_subprocess_output
 from numpy.distutils.fcompiler import FCompiler
-from numpy.distutils.system_info import system_info
 
 compilers = ['GnuFCompiler', 'Gnu95FCompiler']
 
diff --git a/numpy/distutils/fcompiler/pg.py b/numpy/distutils/fcompiler/pg.py
index f3f96bbf2..eb628cb63 100644
--- a/numpy/distutils/fcompiler/pg.py
+++ b/numpy/distutils/fcompiler/pg.py
@@ -1,7 +1,7 @@
 # http://www.pgroup.com
 import sys
 
-from numpy.distutils.fcompiler import FCompiler, dummy_fortran_file
+from numpy.distutils.fcompiler import FCompiler
 from sys import platform
 from os.path import join, dirname, normpath
 
diff --git a/numpy/distutils/mingw32ccompiler.py b/numpy/distutils/mingw32ccompiler.py
index 475f73718..031b7c95f 100644
--- a/numpy/distutils/mingw32ccompiler.py
+++ b/numpy/distutils/mingw32ccompiler.py
@@ -14,7 +14,7 @@ import re
 import textwrap
 
 # Overwrite certain distutils.ccompiler functions:
-import numpy.distutils.ccompiler
+import numpy.distutils.ccompiler  # noqa: F401
 from numpy.distutils import log
 # NT stuff
 # 1. Make sure libpython<version>.a exists for gcc.  If not, build it.
@@ -26,8 +26,7 @@ import distutils.cygwinccompiler
 from distutils.version import StrictVersion
 from distutils.unixccompiler import UnixCCompiler
 from distutils.msvccompiler import get_build_version as get_build_msvc_version
-from distutils.errors import (DistutilsExecError, CompileError,
-                              UnknownFileError)
+from distutils.errors import UnknownFileError
 from numpy.distutils.misc_util import (msvc_runtime_library,
                                        msvc_runtime_version,
                                        msvc_runtime_major,
diff --git a/numpy/distutils/npy_pkg_config.py b/numpy/distutils/npy_pkg_config.py
index 26a0437fb..951ce5fb8 100644
--- a/numpy/distutils/npy_pkg_config.py
+++ b/numpy/distutils/npy_pkg_config.py
@@ -375,7 +375,6 @@ def read_config(pkgname, dirs=None):
 # pkg-config simple emulator - useful for debugging, and maybe later to query
 # the system
 if __name__ == '__main__':
-    import sys
     from optparse import OptionParser
     import glob
 
diff --git a/numpy/distutils/system_info.py b/numpy/distutils/system_info.py
index ae3f1fa2a..11d7c5a0e 100644
--- a/numpy/distutils/system_info.py
+++ b/numpy/distutils/system_info.py
@@ -177,7 +177,7 @@ from distutils.util import get_platform
 
 from numpy.distutils.exec_command import (
     find_executable, filepath_from_subprocess_output,
-    get_pythonexe)
+    )
 from numpy.distutils.misc_util import (is_sequence, is_string,
                                        get_shared_lib_extension)
 from numpy.distutils.command.config import config as cmd_config
diff --git a/numpy/distutils/tests/test_fcompiler.py b/numpy/distutils/tests/test_fcompiler.py
index c559becf8..dd97f1e72 100644
--- a/numpy/distutils/tests/test_fcompiler.py
+++ b/numpy/distutils/tests/test_fcompiler.py
@@ -1,6 +1,4 @@
-import pytest
-
-from numpy.testing import assert_, suppress_warnings
+from numpy.testing import assert_
 import numpy.distutils.fcompiler
 
 customizable_flags = [
diff --git a/numpy/distutils/tests/test_shell_utils.py b/numpy/distutils/tests/test_shell_utils.py
index 754609a5d..32bd283e5 100644
--- a/numpy/distutils/tests/test_shell_utils.py
+++ b/numpy/distutils/tests/test_shell_utils.py
@@ -1,6 +1,5 @@
 import pytest
 import subprocess
-import os
 import json
 import sys
 
diff --git a/numpy/f2py/__init__.py b/numpy/f2py/__init__.py
index 65ad4da72..b74874075 100644
--- a/numpy/f2py/__init__.py
+++ b/numpy/f2py/__init__.py
@@ -8,8 +8,6 @@ import sys
 import subprocess
 import os
 
-import numpy as np
-
 from . import f2py2e
 from . import f2py_testing
 from . import diagnose
diff --git a/numpy/f2py/capi_maps.py b/numpy/f2py/capi_maps.py
index bbfcf1a24..c362fb008 100644
--- a/numpy/f2py/capi_maps.py
+++ b/numpy/f2py/capi_maps.py
@@ -19,7 +19,6 @@ f2py_version = __version__.version
 import copy
 import re
 import os
-import sys
 from .crackfortran import markoutercomma
 from . import cb_rules
 
diff --git a/numpy/f2py/tests/test_crackfortran.py b/numpy/f2py/tests/test_crackfortran.py
index 796965e6f..18a1474b0 100644
--- a/numpy/f2py/tests/test_crackfortran.py
+++ b/numpy/f2py/tests/test_crackfortran.py
@@ -1,5 +1,3 @@
-import pytest
-
 import numpy as np
 from numpy.testing import assert_array_equal
 from . import util
diff --git a/numpy/f2py/tests/test_quoted_character.py b/numpy/f2py/tests/test_quoted_character.py
index d89ef1385..20c77666c 100644
--- a/numpy/f2py/tests/test_quoted_character.py
+++ b/numpy/f2py/tests/test_quoted_character.py
@@ -2,7 +2,6 @@
 
 """
 import sys
-from importlib import import_module
 import pytest
 
 from numpy.testing import assert_equal
diff --git a/numpy/fft/tests/test_helper.py b/numpy/fft/tests/test_helper.py
index 2b457271b..68f5990af 100644
--- a/numpy/fft/tests/test_helper.py
+++ b/numpy/fft/tests/test_helper.py
@@ -4,7 +4,7 @@ Copied from fftpack.helper by Pearu Peterson, October 2005
 
 """
 import numpy as np
-from numpy.testing import assert_array_almost_equal, assert_equal
+from numpy.testing import assert_array_almost_equal
 from numpy import fft, pi
 
 
diff --git a/numpy/fft/tests/test_pocketfft.py b/numpy/fft/tests/test_pocketfft.py
index 14f92c081..7c3db0485 100644
--- a/numpy/fft/tests/test_pocketfft.py
+++ b/numpy/fft/tests/test_pocketfft.py
@@ -5,7 +5,6 @@ from numpy.testing import (
         assert_array_equal, assert_raises, assert_allclose
         )
 import threading
-import sys
 import queue
 
 
diff --git a/numpy/lib/_datasource.py b/numpy/lib/_datasource.py
index 76cc306b7..f5d0cc217 100644
--- a/numpy/lib/_datasource.py
+++ b/numpy/lib/_datasource.py
@@ -35,7 +35,6 @@ Example::
 
 """
 import os
-import sys
 import shutil
 import io
 from contextlib import closing
diff --git a/numpy/ma/mrecords.py b/numpy/ma/mrecords.py
index a154cbbc8..cd93a9a14 100644
--- a/numpy/ma/mrecords.py
+++ b/numpy/ma/mrecords.py
@@ -13,7 +13,6 @@ and the masking of individual fields.
 #  first place, and then rename the invalid fields with a trailing
 #  underscore. Maybe we could just overload the parser function ?
 
-import sys
 import warnings
 
 import numpy as np
diff --git a/numpy/random/tests/test_extending.py b/numpy/random/tests/test_extending.py
index b0d4c60fe..64b8803dd 100644
--- a/numpy/random/tests/test_extending.py
+++ b/numpy/random/tests/test_extending.py
@@ -50,8 +50,8 @@ def test_cython(tmp_path):
 @pytest.mark.skipif(numba is None or cffi is None,
                     reason="requires numba and cffi")
 def test_numba():
-    from numpy.random._examples.numba import extending
+    from numpy.random._examples.numba import extending  # noqa: F401
 
 @pytest.mark.skipif(cffi is None, reason="requires cffi")
 def test_cffi():
-    from numpy.random._examples.cffi import extending
+    from numpy.random._examples.cffi import extending  # noqa: F401
diff --git a/numpy/testing/_private/parameterized.py b/numpy/testing/_private/parameterized.py
index 382585345..3bd8ede91 100644
--- a/numpy/testing/_private/parameterized.py
+++ b/numpy/testing/_private/parameterized.py
@@ -31,7 +31,6 @@ either expressed or implied, of David Wolever.
 
 """
 import re
-import sys
 import inspect
 import warnings
 from functools import wraps
diff --git a/numpy/testing/tests/test_utils.py b/numpy/testing/tests/test_utils.py
index 913c67fc6..b899e94f4 100644
--- a/numpy/testing/tests/test_utils.py
+++ b/numpy/testing/tests/test_utils.py
@@ -2,7 +2,6 @@ import warnings
 import sys
 import os
 import itertools
-import textwrap
 import pytest
 import weakref
 
diff --git a/numpy/tests/test_reloading.py b/numpy/tests/test_reloading.py
index a6d2e62a9..860832be8 100644
--- a/numpy/tests/test_reloading.py
+++ b/numpy/tests/test_reloading.py
@@ -1,5 +1,3 @@
-import sys
-
 from numpy.testing import assert_raises, assert_, assert_equal
 from numpy.compat import pickle
 
diff --git a/numpy/tests/test_scripts.py b/numpy/tests/test_scripts.py
index 658606f82..a0f2ba70a 100644
--- a/numpy/tests/test_scripts.py
+++ b/numpy/tests/test_scripts.py
@@ -9,7 +9,7 @@ from os.path import join as pathjoin, isfile, dirname
 import subprocess
 
 import numpy as np
-from numpy.testing import assert_, assert_equal
+from numpy.testing import assert_equal
 
 is_inplace = isfile(pathjoin(dirname(np.__file__),  '..', 'setup.py'))
 
diff --git a/numpy/tests/test_warnings.py b/numpy/tests/test_warnings.py
index c4c206542..d7a6d880c 100644
--- a/numpy/tests/test_warnings.py
+++ b/numpy/tests/test_warnings.py
@@ -2,7 +2,6 @@
 Tests which scan for certain occurrences in the code, they may not find
 all of these occurrences but should catch almost all.
 """
-import sys
 import pytest
 
 from pathlib import Path