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trying to install numpy in python3.9 and getting error in preparing wheel metadata in windows 10. I did not checked using virtual environment
When trying to install numpy I am getting the following error:
C:\Users\lenovo>pip install numpy
Collecting numpy
  Using cached numpy-1.19.2.zip (7.3 MB)
  Installing build dependencies ... done
  Getting requirements to build wheel ... done
    Preparing wheel metadata ... error
    ERROR: Command errored out with exit status 1:
     command: 'c:\users\lenovo\appdata\local\programs\python\python39\python.exe' 'c:\users\lenovo\appdata\local\programs\python\python39\lib\site-packages\pip\_vendor\pep517\_in_process.py' prepare_metadata_for_build_wheel 'C:\Users\lenovo\AppData\Local\Temp\tmpmtdh020c'
         cwd: C:\Users\lenovo\AppData\Local\Temp\pip-install-c07n3_wi\numpy
    Complete output (200 lines):
    Running from numpy source directory.
    setup.py:470: UserWarning: Unrecognized setuptools command, proceeding with generating Cython sources and expanding templates
      run_build = parse_setuppy_commands()
    Processing numpy/random\_bounded_integers.pxd.in
    Processing numpy/random\bit_generator.pyx
    Processing numpy/random\mtrand.pyx
    Processing numpy/random\_bounded_integers.pyx.in
    Processing numpy/random\_common.pyx
    Processing numpy/random\_generator.pyx
    Processing numpy/random\_mt19937.pyx
    Processing numpy/random\_pcg64.pyx
    Processing numpy/random\_philox.pyx
    Processing numpy/random\_sfc64.pyx
    Cythonizing sources
    blas_opt_info:
    blas_mkl_info:
    No module named 'numpy.distutils._msvccompiler' in numpy.distutils; trying from distutils
    customize MSVCCompiler
      libraries mkl_rt not found in ['c:\\users\\lenovo\\appdata\\local\\programs\\python\\python39\\lib', 'C:\\', 'c:\\users\\lenovo\\appdata\\local\\programs\\python\\python39\\libs']
      NOT AVAILABLE

    blis_info:
      libraries blis not found in ['c:\\users\\lenovo\\appdata\\local\\programs\\python\\python39\\lib', 'C:\\', 'c:\\users\\lenovo\\appdata\\local\\programs\\python\\python39\\libs']
      NOT AVAILABLE

    openblas_info:
      libraries openblas not found in ['c:\\users\\lenovo\\appdata\\local\\programs\\python\\python39\\lib', 'C:\\', 'c:\\users\\lenovo\\appdata\\local\\programs\\python\\python39\\libs']
    get_default_fcompiler: matching types: '['gnu', 'intelv', 'absoft', 'compaqv', 'intelev', 'gnu95', 'g95', 'intelvem', 'intelem', 'flang']'
    customize GnuFCompiler
    Could not locate executable g77
    Could not locate executable f77
    customize IntelVisualFCompiler
    Could not locate executable ifort
    Could not locate executable ifl
    customize AbsoftFCompiler
    Could not locate executable f90
    customize CompaqVisualFCompiler
    Could not locate executable DF
    customize IntelItaniumVisualFCompiler
    Could not locate executable efl
    customize Gnu95FCompiler
    Could not locate executable gfortran
    Could not locate executable f95
    customize G95FCompiler
    Could not locate executable g95
    customize IntelEM64VisualFCompiler
    customize IntelEM64TFCompiler
    Could not locate executable efort
    Could not locate executable efc
    customize PGroupFlangCompiler
    Could not locate executable flang
    don't know how to compile Fortran code on platform 'nt'
      NOT AVAILABLE

    atlas_3_10_blas_threads_info:
    Setting PTATLAS=ATLAS
      libraries tatlas not found in ['c:\\users\\lenovo\\appdata\\local\\programs\\python\\python39\\lib', 'C:\\', 'c:\\users\\lenovo\\appdata\\local\\programs\\python\\python39\\libs']
      NOT AVAILABLE

    atlas_3_10_blas_info:
      libraries satlas not found in ['c:\\users\\lenovo\\appdata\\local\\programs\\python\\python39\\lib', 'C:\\', 'c:\\users\\lenovo\\appdata\\local\\programs\\python\\python39\\libs']
      NOT AVAILABLE

    atlas_blas_threads_info:
    Setting PTATLAS=ATLAS
      libraries ptf77blas,ptcblas,atlas not found in ['c:\\users\\lenovo\\appdata\\local\\programs\\python\\python39\\lib', 'C:\\', 'c:\\users\\lenovo\\appdata\\local\\programs\\python\\python39\\libs']
      NOT AVAILABLE

    atlas_blas_info:
      libraries f77blas,cblas,atlas not found in ['c:\\users\\lenovo\\appdata\\local\\programs\\python\\python39\\lib', 'C:\\', 'c:\\users\\lenovo\\appdata\\local\\programs\\python\\python39\\libs']
      NOT AVAILABLE

    accelerate_info:
      NOT AVAILABLE

    C:\Users\lenovo\AppData\Local\Temp\pip-install-c07n3_wi\numpy\numpy\distutils\system_info.py:1914: UserWarning:
        Optimized (vendor) Blas libraries are not found.
        Falls back to netlib Blas library which has worse performance.
        A better performance should be easily gained by switching
        Blas library.
      if self._calc_info(blas):
    blas_info:
      libraries blas not found in ['c:\\users\\lenovo\\appdata\\local\\programs\\python\\python39\\lib', 'C:\\', 'c:\\users\\lenovo\\appdata\\local\\programs\\python\\python39\\libs']
      NOT AVAILABLE

    C:\Users\lenovo\AppData\Local\Temp\pip-install-c07n3_wi\numpy\numpy\distutils\system_info.py:1914: UserWarning:
        Blas (http://www.netlib.org/blas/) libraries not found.
        Directories to search for the libraries can be specified in the
        numpy/distutils/site.cfg file (section [blas]) or by setting
        the BLAS environment variable.
      if self._calc_info(blas):
    blas_src_info:
      NOT AVAILABLE

    C:\Users\lenovo\AppData\Local\Temp\pip-install-c07n3_wi\numpy\numpy\distutils\system_info.py:1914: UserWarning:
        Blas (http://www.netlib.org/blas/) sources not found.
        Directories to search for the sources can be specified in the
        numpy/distutils/site.cfg file (section [blas_src]) or by setting
        the BLAS_SRC environment variable.
      if self._calc_info(blas):
      NOT AVAILABLE

    non-existing path in 'numpy\\distutils': 'site.cfg'
    lapack_opt_info:
    lapack_mkl_info:
      libraries mkl_rt not found in ['c:\\users\\lenovo\\appdata\\local\\programs\\python\\python39\\lib', 'C:\\', 'c:\\users\\lenovo\\appdata\\local\\programs\\python\\python39\\libs']
      NOT AVAILABLE

    openblas_lapack_info:
      libraries openblas not found in ['c:\\users\\lenovo\\appdata\\local\\programs\\python\\python39\\lib', 'C:\\', 'c:\\users\\lenovo\\appdata\\local\\programs\\python\\python39\\libs']
      NOT AVAILABLE

    openblas_clapack_info:
      libraries openblas,lapack not found in ['c:\\users\\lenovo\\appdata\\local\\programs\\python\\python39\\lib', 'C:\\', 'c:\\users\\lenovo\\appdata\\local\\programs\\python\\python39\\libs']
      NOT AVAILABLE

    flame_info:
      libraries flame not found in ['c:\\users\\lenovo\\appdata\\local\\programs\\python\\python39\\lib', 'C:\\', 'c:\\users\\lenovo\\appdata\\local\\programs\\python\\python39\\libs']
      NOT AVAILABLE

    atlas_3_10_threads_info:
    Setting PTATLAS=ATLAS
      libraries lapack_atlas not found in c:\users\lenovo\appdata\local\programs\python\python39\lib
      libraries tatlas,tatlas not found in c:\users\lenovo\appdata\local\programs\python\python39\lib
      libraries lapack_atlas not found in C:\
      libraries tatlas,tatlas not found in C:\
      libraries lapack_atlas not found in c:\users\lenovo\appdata\local\programs\python\python39\libs
      libraries tatlas,tatlas not found in c:\users\lenovo\appdata\local\programs\python\python39\libs
    <class 'numpy.distutils.system_info.atlas_3_10_threads_info'>
      NOT AVAILABLE

    atlas_3_10_info:
      libraries lapack_atlas not found in c:\users\lenovo\appdata\local\programs\python\python39\lib
      libraries satlas,satlas not found in c:\users\lenovo\appdata\local\programs\python\python39\lib
      libraries lapack_atlas not found in C:\
      libraries satlas,satlas not found in C:\
      libraries lapack_atlas not found in c:\users\lenovo\appdata\local\programs\python\python39\libs
      libraries satlas,satlas not found in c:\users\lenovo\appdata\local\programs\python\python39\libs
    <class 'numpy.distutils.system_info.atlas_3_10_info'>
      NOT AVAILABLE

    atlas_threads_info:
    Setting PTATLAS=ATLAS
      libraries lapack_atlas not found in c:\users\lenovo\appdata\local\programs\python\python39\lib
      libraries ptf77blas,ptcblas,atlas not found in c:\users\lenovo\appdata\local\programs\python\python39\lib
      libraries lapack_atlas not found in C:\
      libraries ptf77blas,ptcblas,atlas not found in C:\
      libraries lapack_atlas not found in c:\users\lenovo\appdata\local\programs\python\python39\libs
      libraries ptf77blas,ptcblas,atlas not found in c:\users\lenovo\appdata\local\programs\python\python39\libs
    <class 'numpy.distutils.system_info.atlas_threads_info'>
      NOT AVAILABLE

    atlas_info:
      libraries lapack_atlas not found in c:\users\lenovo\appdata\local\programs\python\python39\lib
      libraries f77blas,cblas,atlas not found in c:\users\lenovo\appdata\local\programs\python\python39\lib
      libraries lapack_atlas not found in C:\
      libraries f77blas,cblas,atlas not found in C:\
      libraries lapack_atlas not found in c:\users\lenovo\appdata\local\programs\python\python39\libs
      libraries f77blas,cblas,atlas not found in c:\users\lenovo\appdata\local\programs\python\python39\libs
    <class 'numpy.distutils.system_info.atlas_info'>
      NOT AVAILABLE

    lapack_info:
      libraries lapack not found in ['c:\\users\\lenovo\\appdata\\local\\programs\\python\\python39\\lib', 'C:\\', 'c:\\users\\lenovo\\appdata\\local\\programs\\python\\python39\\libs']
      NOT AVAILABLE

    C:\Users\lenovo\AppData\Local\Temp\pip-install-c07n3_wi\numpy\numpy\distutils\system_info.py:1748: UserWarning:
        Lapack (http://www.netlib.org/lapack/) libraries not found.
        Directories to search for the libraries can be specified in the
        numpy/distutils/site.cfg file (section [lapack]) or by setting
        the LAPACK environment variable.
      return getattr(self, '_calc_info_{}'.format(name))()
    lapack_src_info:
      NOT AVAILABLE

    C:\Users\lenovo\AppData\Local\Temp\pip-install-c07n3_wi\numpy\numpy\distutils\system_info.py:1748: UserWarning:
        Lapack (http://www.netlib.org/lapack/) sources not found.
        Directories to search for the sources can be specified in the
        numpy/distutils/site.cfg file (section [lapack_src]) or by setting
        the LAPACK_SRC environment variable.
      return getattr(self, '_calc_info_{}'.format(name))()
      NOT AVAILABLE

    numpy_linalg_lapack_lite:
      FOUND:
        language = c
        define_macros = [('HAVE_BLAS_ILP64', None), ('BLAS_SYMBOL_SUFFIX', '64_')]

    c:\users\lenovo\appdata\local\programs\python\python39\lib\distutils\dist.py:274: UserWarning: Unknown distribution option: 'define_macros'
      warnings.warn(msg)
    running dist_info
    running build_src
    build_src
    building py_modules sources
    creating build
    creating build\src.win-amd64-3.9
    creating build\src.win-amd64-3.9\numpy
    creating build\src.win-amd64-3.9\numpy\distutils
    building library "npymath" sources
    error: Microsoft Visual C++ 14.0 is required. Get it with "Build Tools for Visual Studio": https://visualstudio.microsoft.com/downloads/
    ----------------------------------------
ERROR: Command errored out with exit status 1: 'c:\users\lenovo\appdata\local\programs\python\python39\python.exe' 'c:\users\lenovo\appdata\local\programs\python\python39\lib\site-packages\pip\_vendor\pep517\_in_process.py' prepare_metadata_for_build_wheel 'C:\Users\lenovo\AppData\Local\Temp\tmpmtdh020c' Check the logs for full command output.

So, why is it happening?

Python 3.9 came out 3 days ago (today - Oct 8, 2020). It doesn't have wheels for numpy yet.
See here

But it’s so soon after 3.9’s release, many packages don’t have wheels
for Python 3.9 yet. For example, as of October 6th neither the PyPI
file listing for NumPy (a Pandas dependency) nor the file listing for
Pandas show Python 3.9 wheels. You can, of course, compile these
packages from source, assuming they work out of the box with Python
3.9–but that takes a bunch more effort (setting up compilers) and time.

Is there a specific reason you really need 3.9 right now?
If not, I would stick with 3.8 or even 3.7 for now. Upgrading later should be super easy.

Or they can use pip install pipwin, pipwin install numpy, because Gohlke already has the numpy wheels built for 3.9 (as well as most other popular Python packages that require a compiler).
