[Tutor] "Python not recognized as a command"

[Marc Tompkins]

On Sat, Sep 1, 2018 at 10:40 AM, Dana O'Connor <oconnord at allegheny.edu>
wrote:

> Hi,
> I've been trying to download and use Python 3.7 for the past few days and
> every time I try to open it it tells me I don't have "pip" which should be
> impossible because this version of Python is supposed to automatically come
> with pip (?).  Additionally, whenever I open the command prompt on my
> computer, the command "python" is not even recognized by the system even
> though Python is downloaded onto the computer.  I cannot use Python at all
> until I figure out this problem, so I guess my overall question is why
> doesn't my computer acknowledge Python when it has been downloaded (and
> redownloaded) several times on my computer?
>

A bit more on Alan's point:
I believe that your question is a bit more of an operating system question
than purely a Python question; I also suspect (though I could be wrong)
that your previous experience has been with iOS or Android, and that you're
relatively unfamiliar with older desktop operating systems.
In iOS and Android, programs are packaged in such a way (and the package
installer is configured in such a way) that "downloading" and "installing"
are practically the same thing.  Apple OSx is nearly as seamless, and the
various Linux distros have been trying to move in this direction as well.
Even Windows - with "Universal" apps in Windows 8 and 10 - has been moving
in this direction.

But traditional "desktop"-side Windows, and traditional Windows programs
such as Python, still leave many details to the the user, and so the
process involves a few steps:
-  You download the installer.  This is actually a combination package: a
compressed archive of the actual program you want, wrapped up with a
program that knows how to unpack the archive, distribute its contents to
the appropriate locations, and register its various bits with the operating
system.
-  Once you've downloaded the installer, you run it, and it does its
magic.  It may prompt you to make some choices about where to put things.
-  Now that you've installed the program (Python in this case), you can run
it.  BUT - when you type a command at the prompt, the operating system
needs to know where to find the program file to fulfill your request.
That's where the PATH comes in - it's a list of locations where the OS can
look for, e.g. "python.exe" when you type "python" at the prompt.
-  PATH is a system variable, and it should be set by the installer when
you run it.  But the installer is a program, and sometimes programs fail.
So it's possible that you'd need to fix that; it's easy to do, but we need
more info first.

Hope that helps -