Deletion of Environmental Variables

[Terry Reedy]

On 1/6/2019 9:56 PM, Logan Vogelsong wrote:
> I planned on using python to simulate different cipher to challenge myself,
> but I kinda deleted my environmental variables to python. I run Windows 10
> and wanted to get NumPy and MatPlotLib modules imported to python.
> 
> Basically, I downloaded python 3.7.1 first, but when I realized it was not
> compatible with TensorFlow (I wanted to make a machine learning algorithm
> at a point in time), I uninstalled it to get python 3.6.1.

Windows easily allows multiple versions to be installed.  The py 
launcher lets you easily pick which to run (from a command console).

For 3.6, use the latest release, now 3.6.8, which has hundreds of fixes 
since 3.6.1.

If you have multiple versions, you must install 3rd party modules for 
each version you want to import them into.


  Somehow, maybe I
> misread a stack overflow post, but I deleted all my path files to python36
> for whatever reason. I still have no idea why I did this. Then, I thought,
> if I could uninstall python 3.6.1 and reinstall it pip would come back and
> I could use python from the cmd. I uninstalled it and tried reinstalling
> (with chocolatey this time) it for no avail. I tried searching for all the
> correct environment variables to put them back in manually, but I cannot
> seem to find most of them since python is still “not recognized as an
> internal or external command, operable program or batch file.”

There is, or at least used to be, an option to add the python directly 
to PATH.  But using py instead python is needed anyway to select from 
multiple versions.

> In my cmd. I really want pip to work so I can download modules.

By default, the PSF Windows installer installs pip, using the ensurepip 
module.  If this did not happen, you can run it yourself. See
https://docs.python.org/3/library/ensurepip.html

The pydev recommended way to run pip on windows is
 > py -x.y pip <pip options>
as this installs the package requested into the x.y site-packages 
directory.

-- 
Terry Jan Reedy