Thursday, 13 September 2018

How to install Python on Windows?

How to install the latest version of Python?

  • Go to Python Releases for Windows page and click the link for the latest release, e.g. Latest Python 3 Release - Python 3.7.0
  • Scroll to the bottom of the page and click on the link of the installer to download it. I opted for "Windows x86-64 web-based installer".
  • Run the installer. On the first page of the installer opt for adding Python to PATH.
  • Python will be installed in C:\Users\User\AppData\Local\Programs\Python\Python37.

If you haven't opted for adding Python to PATH during installation, you open a Terminal and try to run Python interpreter by typing python you'll get:

>python
'python' is not recognized as an internal or external command,
operable program or batch file.

To resolve this and make python binary visible from every directory add its path to Path environment variable. After that, python interpreter is visible from anywhere (in a new Terminal session):

>python
Python 3.7.0 (v3.7.0:1bf9cc5093, Jun 27 2018, 04:59:51) [MSC v.1914 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>>


How to install multiple versions of Python on the same system?


Sometimes you need to have on your machine installed various versions of Python e.g. some applications might require Python 2 and some Python 3. I already installed Python 3 above and now I'm gonna install Python 2:
  • Go to Python Releases for Windows page and click the link for the latest release, e.g. Latest Python 2 Release - Python 2.7.15
  • Scroll to the bottom of the page and click on the link of the installer to download it. I opted for "Windows x86-64 MSI installer".
  • Run the installer. On the first page of the installer you can opt for adding Python 2 to PATH.
  • Python will be installed in C:\Python27.
If you opt for adding Python 2 to Path, restart the Terminal (so it can pick up the latest values of environment variables) and type python, Terminal will pick Python 2:

>python
Python 2.7.15 (v2.7.15:ca079a3ea3, Apr 30 2018, 16:30:26) [MSC v.1500 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>>

Python 2 installer has added C:\Python27 (and C:\Python27\Scripts) as first entries in PATH variable so Terminal now picks python.exe from this directory.

To make sure you are using desired version of Python interpreter in Terminal the best is to remove all Python paths from PATH and then set path to desired Python version for the current Terminal session (temporarily) by executing:

>set PATH=path\to\desired\python;%PATH%

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